Western journalists James Foley and John Cantlie converted to Islam while being held hostage in Syria, a Belgian newspaper quoted a jihadist suspect as saying Wednesday, adding that the pair may have been forced to do so.

Foley, an American, was beheaded by the Islamic State (IS) group last month, while Cantlie, a Briton, is believed to be still in captivity.

Saudi pilots who conducted air strikes on jihadists in Syria received online death threats Wednesday after photos were published of those involved, among them a son of the crown prince.

The official Saudi Press Agency (SPA) released photographs of eight airmen it said were involved in Tuesday's U.S.-led operation, carried out with Gulf allies.

Germany said Wednesday it would not change its policy following a reported threat by Philippine Islamist militants to kill a German hostage unless Berlin stops backing U.S. action against jihadists in Iraq and Syria.

"We heard about the report and I would like to say one thing: threats are not an appropriate way to influence our policy in Syria and Iraq," a foreign ministry spokeswoman said.

Lebanese Forces leader Samir Geagea questioned on Wednesday Hizbullah chief Sayyed Hassan Nasrallah's opposition to the United States-led strikes against jihadist Islamic State positions in the region.

He asked Nasrallah: “Would you have maintained your initial rejection of the international coalition against the IS had Iran been part of it?”

U.S. airstrikes in Syria have had an "important impact," U.S. national security adviser Susan Rice said Wednesday, but it is unclear if they have killed the head of the Khorasan group, an Al-Qaida offshoot.

The strikes by U.S. warplanes and cruise missiles targeted the Islamic State movement as well as the little-known Khorasan group, which Washington said has said was plotting attacks against U.S. targets.

U.S. strikes have killed a senior operative from Al-Qaida's Syrian branch in the war-torn country's northern province of Aleppo, activists said on Wednesday.

Abu Yusef al-Turki, a 47-year-old Turkish fighter, was among 50 militants killed in strikes on Tuesday against what the United States called an Al-Qaida cell that had been planning attacks on Western interests.

France's interior minister on Wednesday announced a probe into a series of blunders that saw three suspected jihadists waltz out of a French airport after being transferred from Turkish custody.

Authorities were left red-faced after an announcement they had arrested the three men at a Paris airport turned out to be false.

Turkey on Wednesday said neither its airspace nor a strategic air base on its territory were used in the latest U.S.-led strikes against Islamic State (IS) insurgents in Syria, a Turkish official said.

"The answer is clear: Neither the (Turkish) airspace nor the Incirlik (air base) were used," the official told AFP in Ankara on condition of anonymity. Incirlik air base in southern Turkey is used by both U.S. and Turkish forces.

The U.S.-led coalition launched strikes against Islamic State militants besieging a Kurdish town in Syria as world leaders prepared for talks on Wednesday at the U.N. on battling the jihadists and as the attacks forced the Islamists to evacuate their Syria bases.

The overnight raids targeted Islamic State (IS) group fighters whose fierce assault in the area prompted more than 130,000 civilians to flee across the border into Turkey.

President Barack Obama thanked Arab leaders Tuesday for joining a US-led coalition aimed at defeating Islamic extremists, winning pledges from his allies that they were in the fight for the long haul.

Speaking just hours after he launched air strikes against the Islamic State group in Syria, Obama said the coalition "represents partners and friends with which we have worked for many, many years to make sure that security and prosperity exists in this region."