Russia believes U.S.-led air strikes against jihadists in Syria should be carried out in coordination with Syrian authorities and in accordance with international law, Foreign Minister Sergei Lavrov said Friday.

Lavrov was speaking after the United States this week extended an air assault against the Islamic State (IS) group in Iraq to Syria with the support of five Arab countries.

A senior Islamic State group jihadist was killed on Friday in an air strike in eastern Syria, the Syrian Observatory for Human Rights said.

"A coalition warplane fired on a motorbike with two men on it after it left a headquarters" of IS west of Deir Ezzor city in the province of the same name, the head of the Britain-based monitor told AFP.

Hundreds of Kurds on Friday broke through the Turkish border into Syrian territory to join Kurdish forces battling the advance of Islamic State (IS) militants around the Syrian town of Ain al-Arab.

Turkish security forces have on previous occasions halted activists from moving into Syria to fight IS, sparking clashes with local Kurds on the border.

Jihadists with the Islamic State group have stopped oil extraction from fields in Deir Ezzor province in eastern Syria after U.S.-led strikes targeted refineries, activists told AFP on Friday.

"Oil extraction has been halted because of the security situation," said Leith al-Deiri, an activist in Deir Ezzor who spoke to AFP via the Internet.

Hundreds of people gathered in Paris Friday answering a call by Muslim leaders to denounce the "barbarism" of Islamic State militants, as flags across France flew at half mast after the beheading of a French national.

Imams and ordinary Muslims have rallied to condemn the execution of 55-year-old mountaineer Herve Gourdel this week by militants in Algeria with ties to the IS jihadists, as the country mourned the brutal murder.

Turkey said Friday it was prepared to take any measure that ensures its own security in the fight against Islamic State militants, keeping Ankara's options open amid growing pressure from its Western allies for concrete action.

Ankara has for months frustrated the West with its distinctly low-key role in the campaign against IS jihadists but there have been signs over the last days it is shifting its approach.

U.S. authorities believe the Islamic State jihadists will try to stage an attack in America in reprisal for U.S.-led air strikes in Syria, the head of the FBI said Thursday.

"There's no doubt," said director James Comey told reporters. "They want to do things in retaliation for America's actions or its allies."

British lawmakers on Friday voted overwhelmingly to join anti-jihadist air strikes in Iraq as U.S.-led raids in Syria disrupted the Islamic State group's lucrative oil-pumping operations.

The House of Commons voted by a majority of 524 to 43 after the main political parties all approved military action saying that "lessons from the past" of the 2003 Iraq war had been learned.

The emir of Qatar has denied accusations that his country funds extremist groups in Syria, while stressing the Gulf state's commitment to the U.S.-led campaign against Islamic State jihadists.

"We don't fund extremists," Sheikh Tamim bin Hamad al-Thani said in an interview with CNN aired Thursday. "If you talk about certain movements, especially in Syria and Iraq, we all consider them terrorist movement."

Lebanese Forces leader Samir Geagea noted on Friday that the state is faced with two options regarding the release of the soldiers and policemen held captive by Islamist militants from Syria.

He said via Twitter: “The army should attempt to free them by force, which requires complete coordination with the international coalition against the Islamic State group.”