(Reuters) - Islamic State fighters tightened their siege of a town on Syria's border with Turkey on Friday despite U.S.-led air strikes aimed at defeating the militants in both Syria and Iraq, in a coalition which has now drawn widespread European support.

Washington's closest ally in the wars of the last decade joined the alliance at last on Friday after weeks of weighing its options: Britain's parliament voted 542 to 43 to back Prime Minister David Cameron's decision to join air strikes on Iraq.

Belgium's parliament also voted 114 to 2 on Friday to take part and Denmark said it would send planes. Six Belgian F-16s took off for a staging post in Greece even before the vote.

"This is not a threat on the far side of the world. Left unchecked, we will face a terrorist caliphate on the shores of the Mediterranean and bordering a NATO member, with a declared and proven intention to attack our country and our people," Cameron told British lawmakers.

Until this week France was the only Western country to answer President Barack Obama's call to join the U.S.-led campaign. Since Monday, Australia and the Netherlands have also joined. On Friday Germany expressed support for the mission despite saying it would not send aircraft of its own.

Obama has sought to rally international support for a military coalition against Islamic State, a powerful force in Syria which swept through much of northern Iraq in June, slaughtering prisoners and ordering Shi'ites and non-Muslims to convert or die.

The campaign has brought Washington back to the battlefield in Iraq that it left in 2011 and into Syria for the first time after avoiding involvement during a civil war that began the same year.

The coalition also includes several Arab states, all led by Sunni Muslims alarmed at the rise of Islamic State.

Islamic State has emerged as the most powerful Sunni militant group battling the Shi'ite-backed governments in Iraq and Syria. Its fighters are also battling against rival Sunni rebel groups in Syria and against Kurds in both Syria and Iraq, countries facing complex, multi-sided civil wars in which nearly every state in the Middle East has a stake.

French public support for the mission surged this week after the beheading of a French tourist in Algeria by captors who said it was retaliation for French participation in strikes in Iraq.

Paris said it might also join U.S. strikes in Syria although there was no plan yet to do so. European countries have so far agreed only to strike targets in Iraq, where the government has asked for help, and not in Syria, where President Bashar al-Assad has not given permission, although he has not objected.

The White House said it was pleased at the British decision and the pace at which the coalition was growing.

"WE'RE AFRAID"

More than a month since Washington began striking Islamic State targets in Iraq, and four days since it extended the campaign into Syria, there are signs fighters are lowering their profile in areas they control to become a harder target.

General Martin Dempsey, chairman of the U.S. Joint Chiefs of Staff, said this week's strikes in Syria had disrupted Islamic State's command, control and logistics capabilities.

But the air campaign has yet to halt the group's advance in Syria, where fighters have laid siege to a Kurdish town on the Turkish border, sending 140,000 refugees across the frontier since last week in the fastest exodus of the three-and-a-half-year-old civil war.

Some Kurdish commanders have said the air campaign has given the militants' advance greater impetus by prompting them to move armor out of positions in cities and send it to the front lines, where Western planes have yet to strike.

The main battle in northern Syria has been visible from across the border in Turkey. The boom of artillery and bursts of machinegun fire echoed across the area and at least two shells hit a vineyard on the Turkish side of the border, though there were no immediate reports of casualties inside Turkey.

"We're afraid. We're taking the car and leaving today," said vineyard owner Huseyin Turkmen, 60, as small arms fire rang out in the Syrian hills just to the south.

Islamic State fighters appeared to have taken control of a hill 10 km (6 miles) west of Kobani from where the YPG, the main Kurdish armed group in northern Syria, had been attacking them in recent days.

The British-based Syrian Observatory for Human Rights, which monitors the war, said Islamic State fighters had also taken control of a village around 7 km (4 miles) east of Kobani.

Kurdish forces said on Thursday they had pushed back the advance on Kobani, also known as Ayn al-Arab, but appealed for U.S.-led air strikes on the insurgents' tanks and heavy weapons.

"The clashes are moving between east, west and south of Kobani ... The three sides are active," Idris Nassan, deputy foreign minister in the area's Kurdish administration, said by phone from the center of the town.

"They are trying hard to reach Kobani. There is resistance here by YPG, by Kobani and some volunteers from north Kurdistan Turkish Kurds," he said. "Every girl, every young man, every man who is able to fight, to carry a gun, they are armed and they are ready to defend and fight."

NATO member Turkey has been conspicuously absent from the coalition against Islamic State, angering its Kurdish residents.

SYRIAN AIR STRIKES

The U.S. military said its planes blew up four Islamic State tanks in eastern Syria and hit a number of targets in Iraq.

The Syrian Observatory monitoring group said one U.S.-led strike in eastern Syria had killed an "important" Islamic State figure on a motorbike. It did not identify the victim.

Assad's Syrian government has not objected to the U.S.-led campaign against some of his most powerful foes. Washington says it wants to defeat Islamic State without helping Assad remain in power and hopes other anti-Assad groups can fill the vacuum.

But while U.S. planes have been striking Islamic State in eastern Syria, Assad's air force has been bombing other rebel groups in the west of the country, and his troops and allied Lebanese Shi'ite militia have advanced.

Syrian warplanes dropped projectiles including "barrel bombs" - oil drums filled with explosives - in Hama, Idlib, Homs and Aleppo provinces and around Damascus, the Observatory said.

Five people were killed when barrel bombs were dropped on al-Rastan city in Homs province and nine died in a barrel bomb attack east of the city of Aleppo, it said.

In Iraq, where the U.S. strikes have gone on for far longer and Washington is supporting government efforts to advance, Islamic State militants are changing tactics, ditching conspicuous convoys in favor of motorcycles and planting their black flags on civilian homes to confuse target spotters.

Witnesses and tribal sources in Islamic State-controlled areas report fewer militant checkpoints to weed out "apostates" and less cell phone use.Islamic State elements "abandoned one of their biggest headquarters in the village" when they heard the air strike campaign was likely to target their area, said a tribal sheikh from a village south of Kirkuk.

"They took all their furniture, vehicles and weapons. Then they planted roadside bombs and destroyed the headquarters," said the sheikh who declined to be identified. "They don't move in military convoys like before. Instead they use motorcycles, bicycles, and if necessary, they use camouflaged cars."

Tribal and local intelligence sources said an air strike on Thursday near Bashir town, 20 km (12 miles) south of Kirkuk, had killed two local senior Islamic State leaders while they were receiving a group of militants from Syria and Mosul. Ongoing fighting makes it impossible to verify the reports.

Sheikh Anwar al-Assy al-Obeidi, the head of a large tribe in Kirkuk and across Iraq, told Reuters there were now fewer killings because fighters could not operate as openly.

"They were executing people like drinking water ... Now the air strikes are very active and have decreased the (militants') ability," said Obeidi, who fled to Iraqi Kurdish-held territory this summer after Islamic State blew up his home.

(AP) — U.S.-led airstrikes targeted Syrian oil installations held by the extremist Islamic State group overnight and early Thursday, killing at least 19 people as more families of militants left their key stronghold, fearing further raids, activists said.

The strikes aimed to knock out one of the militants' main revenue streams — black market oil sales that the U.S. says earn up to $2 million a day for the group. That funding, along with a further estimated $1 million a day from other smuggling, theft and extortion, has been crucial in enabling the extremists to overrun much of Syria and neighboring Iraq.

The United States and its Arab allies have been carrying out strikes in Syria for the past three days, trying to uproot the group, which has carved out a self-declared state straddling the border, imposed a harsh version of Islamic law and massacred opponents. The U.S. has been conducting air raids against the group in neighboring Iraq for more than a month.

On the ground, Syria's civil war raged on unabated, with government forces taking back an important industrial area near Damascus from the rebels, according to Syrian activists and state media. Activists also accused President Bashar Assad's troops of using an unspecified deadly chemical substance.

The Islamic State group is believed to control 11 oil fields in Iraq and Syria. The new strikes involved six U.S. warplanes and 10 more from the United Arab Emirates and Saudi Arabia, mainly hitting small-scale refineries used by the militants in eastern Syria, Pentagon spokesman Rear Adm. John Kirby said.

At least 14 militants were killed, according to the Britain-based Syrian Observatory for Human Rights, which monitors the Syrian conflict through a network of activists on the ground.

The Observatory and two independent activists said another five people who lived near one of the refineries were also killed, likely the wives and children of the militants.

Kirby said the Pentagon is looking into reports that civilians were killed but has no evidence yet.

Other strikes hit checkpoints, compounds, training grounds and vehicles of the Islamic State group in northern and eastern Syria. The raids also targeted two Syrian military bases that had been seized by the Islamic State group. In the eastern Syrian town of Mayadeen, a building used by the militants as an Islamic court was also hit.

Apparently fearing more strikes, the militants reduced the number of fighters on their checkpoints, activists said. Many of the casualties the group has sustained in the American-led air raids have been at checkpoints. Activists also said that more families of Islamic State militants were clearing out of the city of Raqqa, the group's de facto capital, on Thursday, heading eastward.

For some Syrians, the airstrikes were bitter justice.

"God has imposed on you just a part of what you have done, but you are even more criminal," wrote Mahmoud Abdul-Razak on an anti-Islamic State group Facebook page, saying that the airstrikes were divine punishment.

But other Syrians see coalition strikes as serving Assad's interests because they do not target government forces and because some have hit the Nusra Front, Syria's al-Qaida affiliate that has battled both the Islamic State and Assad's forces.

Some opposition activists saw the strikes on the Nusra Front as a sign of a wider operation targeting other Syrian militants among the anti-Assad rebellion seen as a potential threat by the United States.

"All of this is to serve Bashar, and yet people believe the Americans are protecting the Syrians," said Saad Saad, writing on the same Facebook page.

A rebel fighter in the northern Aleppo province who only identified himself by his nom de guerre, Ramy, said the U.S. airstrikes appear coordinated with the flights of Syrian military planes, which would disappear from the skies shortly before the U.S.-led coalition aircraft show up.

"It's like they coordinate with each other," Ramy told The Associated Press over Skype. "The American planes come and they go."

The Observatory reported fewer Syrian airstrikes in the past three days — likely because of the presence of the coalition aircraft. Still, bombing continued in a rebel-held area near Damascus, killing at least 8 people, including children, reported the Observatory and activist Hassan Taqulden.

Syrian Kurdish fighters also reported three airstrikes near a northern Kurdish area, which Islamic State militants have been attacking for nearly a week, prompting more than 150,000 people to flee to neighboring Turkey.

The Kurdish fighters said the U.S.-led coalition was likely behind the strikes in the area known as Ayn Arab, or Kobani to the Kurds. A spokesman for the fighters, Reydour Khalil, pleaded again that the coalition coordinate with them, claiming that the overnight strikes were not effective and struck abandoned bases.

"We are willing to cooperate with the U.S. and its alliance" by providing positions and information about the militants' movements, Khalil said.

Elsewhere in Syria, Assad's forces wrested back the rebel-held industrial area of Adra near Damascus after months of clashes.

On a government-organized tour of the area Thursday, the smell of dead bodies hung in the air amid the bombed-out buildings and torched cars. An unnamed commander accompanying the journalists said that the military dismantled 17 car bombs, and that soldiers were working to disarm more of them.

The government forces seized the Adra industrial zone after rebels accused them of using chemical explosives there on Wednesday. Footage of the wounded from the incident, in which six people were killed, showed men jerking uncontrollably and struggling to breathe before their bodies went limp.

The footage, posted on social networks, appeared genuine and consistent with The Associated Press reporting of the event depicted. But the footage did not suggest what chemical — if any — was used on the men.

(AP) — Confronted by the growing threat of Middle East militants, President Barack Obama implored world leaders at the United Nations Wednesday to rally behind his expanding military campaign to stamp out the violent Islamic State group and its "network of death."

"There can be no reasoning, no negotiation, with this brand of evil," Obama told the General Assembly. In a striking shift for a president who has been reluctant to take military action in the past, Obama declared that force is the only language the militants understand. He warned those who have joined their cause to "leave the battlefield while they can."

The widening war against the Islamic State was just one in a cascade of crises that confronted the presidents, prime ministers and monarchs at the annual meeting of the U.N. General Assembly. Also vying for attention was Russia's continued provocations in Ukraine, a deadly Ebola outbreak in West Africa, and the plight of civilians caught in conflicts around the world.

"Not since the end of the Second World War have there been so many refugees, displaced people and asylum seekers," U.N. Secretary-General Ban Ki-moon said as he opened Wednesday's session.

In a rare move, Obama also chaired a meeting of the U.N. Security Council where members unanimously adopted a resolution requiring all countries to prevent the recruitment and transport of would-be foreign fighters preparing to join terrorist organizations such as the Islamic State group.

The American-led military campaign in the Middle East was at the center of much of the day's discussions. After weeks of airstrikes in Iraq, U.S. planes began hitting targets in Syria this week, joined by an unexpected coalition of five Arab nations: Bahrain, Saudi Arabia, Jordan, Qatar and the United Arab Emirates.

There were more U.S. and coalition airstrikes Wednesday on both sides of the Syrian-Iraqi border. U.S. and allied planes and drones hit a dozen targets in Syria that included small-scale oil refineries that have been providing millions of dollars to the Islamic State, the U.S. Central Command said. Saudi Arabia and the United Arab Emirates took part in addition to U.S. aircraft.

France has also taken part in strikes in Iraq, and British Prime Minister David Cameron's office announced that Parliament was being recalled to London to debate whether to join the campaign, too.

The Islamic State has made lightning gains in Iraq this year and now moves freely across the increasingly blurred border with Syria. The group has claimed responsibility for the beheading of two American journalists and a British aid worker, sparking outrage in the West and contributing to an increase in public support for military action.

Shortly after Obama's remarks, France confirmed that Algerian extremists allied with the Islamic State group had beheaded one of its citizens after the French ignored demands to stop airstrikes in Iraq. French President Francois Hollande, who was in New York for the U.N. meetings, said the killing underscored why "the fight the international community needs to wage versus terrorism knows no borders."

U.S. officials say they are concerned that foreigners with Western passports could return to their home countries to carry out attacks. And even as Obama welcomed support for the resolution to deter foreign fighters, he said more must be done.

"The words spoken here today must be matched and translated into action," he said.

The threat from the Islamic State group has already drawn Obama back into conflicts in the Middle East that he has long sought to avoid, particularly in Syria, which is mired in a bloody three-year civil war. Just months ago, the president appeared to be on track to fulfill his pledge to end the U.S.-led wars he inherited in Iraq and Afghanistan.

Obama sought to distinguish this current military campaign from those lengthy wars, declaring that he has no intention of sending U.S. troops to occupy foreign lands. He also pressed Middle Eastern nations to look beyond military action and take steps to reject the ideology that has spawned groups like the Islamic State and to cut off funding that has allowed that terror group and others to thrive.

"No external power can bring about a transformation of hearts and minds," Obama said in his nearly 40-minute address.

Apart from the Middle East, the president was particularly blunt in his condemnation of Russia's actions in Ukraine. He accused Moscow of sending arms to pro-Russian separatists, refusing to allow access to the site of a downed civilian airliner and then moving its own troops across the border with Ukraine.

Still, Obama held open the prospect of a resolution to the conflict. While he has previously expressed skepticism about a cease-fire signed this month, he said Wednesday that the agreement "offers an opening" for peace.

If Russia follows through, Obama said, the U.S. will lift economic sanctions that have damaged Russia's economy but so far failed to shift President Vladimir Putin's approach.

The chaotic global landscape Obama described Wednesday stood in contrast to his remarks at the U.N. one year ago, when he touted diplomatic openings on multiple fronts. At the time, the U.S. was embarking on a fresh attempt to forge an elusive peace between Israelis and Palestinians and there were signs of a thaw in the decades-old tensions between the U.S. and Iran.

The Mideast talks have since collapsed, though the president said that "as bleak as the landscape appears, America will never give up the pursuit of peace." And while the U.S., Iran and world powers are now in the midst of nuclear negotiations, those talks are deadlocked and there is skepticism about whether a deal can be reached by a Nov. 24 deadline.

"My message to Iran's leaders and people is simple: Do not let this opportunity pass," Obama said.

Even as the president cast the U.S. as the main driver of peace and security around the world, he acknowledged that his country has not always lived up to its own ideals. He singled out the recent clashes between police and protesters in Ferguson, Missouri, that followed the shooting death of a black teenager.

"Yes, we have our own racial and ethnic tensions," Obama said. "But we welcome the scrutiny of the world. Because what you see in America is a country that has steadily worked to address our problems and make our union more perfect."

(AP) — Some 130,000 Syrian refugees have reached Turkey in the past four days after fleeing the advance of Islamic State militants, Turkey's deputy prime minister said Monday, warning that the number could rise further as the militants press ahead with an onslaught.

Numan Kurtulmus said however, that Turkey was ready to react to "the worst case scenario."

"I hope that we are not faced with a more populous refugee wave, but if we are, we have taken our precautions," Kurtulmus said. "A refugee wave that can be expressed by hundreds of thousands is a possibility."

The refugees have been flooding into Turkey since Thursday, escaping an Islamic State offensive that has pushed the conflict nearly within sight of the Turkish border. The conflict in Syria had already pushed more than a million people over the border in the past 3½ years.

The al-Qaida breakaway group — which says it wants to establish an Islamic state, or caliphate, ruled by a harsh version of Islamic law in territory it captured straddling the Syria-Iraq border — has in recent days advanced into Kurdish regions of Syria that border Turkey, where fleeing refugees on Sunday reported atrocities that included stonings, beheadings and the torching of homes.

On Monday, fighting between Kurdish fighters and the Islamic State militants raged on near the northern city of Kobani, which is also known as Ayn Arab, the Britain-based Syrian Observatory for Human Rights said.

The Observatory said the militants lost at least 21 fighters since Sunday night, most of them on the southern outskirts of Kobani.

Nawaf Khalil, a spokesman for Syria's Kurdish Democratic Union Party, or PYD, told The Associated Press that the situation on the ground "is better than before."

He added that the main Kurdish force in Syria, known as the People's Protection Units, had pushed Islamic State fighters about 10 kilometers (6 miles) away from their previous positions east of Kobani.

"We will fight until the last gunman in Kobani," Khalil said.

The situation at the Turkish side of the border was tense, with more clashes breaking out between Kurds wanting to cross to take aid to the Kobani region and police preventing them from reaching the area.

The nearby town of Suruc was flooded with refugees and armored military vehicles were moving.

 "This is not a natural disaster... What we are faced with is a man-made disaster," said Kurtulmus, the Turkish deputy prime minister.

"We don't know how many more villages may be raided, how many more people may be forced to seek refuge. We don't know," he said. "An uncontrollable force at the other side of the border is attacking civilians. The extent of the disaster is worse than a natural disaster."