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.

Secretary of State John Kerry said Tuesday that Turkey had pledged to take part in the U.S.-led coalition against Islamic militants following the release of 49 Turkish hostages.

"Turkey is very much part of this coalition, and Turkey will be very engaged on the frontlines of this effort," Kerry told a global counter-terrorism forum after meeting with Turkish officials.

The jailed leader of Turkey's outlawed Kurdistan Workers Party (PKK) urged Kurds to join "all-out resistance" against Islamic State militants advancing on Kurdish areas in northern Syria, the pro-Kurdish Firat agency reported Tuesday.

IS extremists have closed in on the strategic Syrian town of Ain al-Arab near the Turkish border, called Kobane in Kurdish, and have seized dozens of villages in the past week, prompting an exodus of refugees into Turkey.

Turkey on Tuesday indicated that dozens of Turkish hostages abducted by Islamic State (IS) insurgents in Iraq may have been freed in exchange for the release of IS militants held by Syrian rebels.

Citing security sources, the Hurriyet daily said that Syrian rebels released 50 members of IS, including the family of a key radical leader, in exchange for the release of Turkish hostages.

The Turkish government announced it was lifting a ban on female students wearing the Islamic headscarf at high schools, in a move denounced by opponents as undermining the basis of the country's secular society.

President Recep Tayyip Erdogan, who co-founded the ruling Islamic-rooted Justice and Development Party (AKP), has long been accused by opponents of eroding the secular values of the modern Turkish state.

The United States and its Arab allies unleashed deadly bomb and missile strikes on jihadists in Syria on Tuesday, opening a new front in the battle against the Islamic State group.

Dozens of IS and Al-Qaida militants were reported to have been killed in the raids, which Washington said had partly targeted extremists plotting an "imminent attack" against the West.

Osmane Sero has been at it since dawn, pacing back and forth in front of a line of Turkish police by the border with Syria.

Clutched in his wrinkled hand is his Syrian passport and a photograph of a smiling five-year-old girl.

Kurdish militia fought to defend a key border town in northern Syria on Monday after 130,000 terrified residents fled to Turkey to escape an advance by Islamic State fighters.

Amid calls for a U.S.-led coalition to support the Kurdish fighters with air strikes, the IS group issued a statement urging Muslims to kill Westerners whose countries have joined the campaign.

Prime Minister Tammam Salam traveled on Monday to New York where he will urge the international community to provide more support to Lebanon before it “drowns” under the burden of the Syrian refugees and the repercussions of the war in the neighboring country.

“I will ask in New York for support for Lebanon before it drowns. I will also stress the importance of helping the state in carrying the burden of the Syrian refugees,” Salam told al-Mustaqbal newspaper in an interview published on Monday.

President Recep Tayyip Erdogan said Sunday dozens of Turkish hostages held by Islamic State militants in Iraq had been freed as a result of negotiations and no ransom had been paid for their release. 

"A bargain for money is totally out of the question. There were only diplomatic and political negotiations. And this is a diplomatic victory," Erdogan told reporters at Ankara's Esenboga Airport before departing for New York for a U.N. General Assembly meeting.