The Turkish army has already stepped up security along parts of the border in recent weeks, as the conflict in Syria involving Kurdish militia fighters, Islamist militants and Syrian security forces intensifies.

Turkey has agreed to allow U.S. warplanes to use its air bases for the first time for bombing missions against Islamic State in Syria, U.S. and Turkish officials said.

The United States has been pressuring a hesitant Turkey to join its coalition against Islamic State since it first began bombing the group last summer.

The U.S. and Turkey have reached a “tentative handshake deal” to increase U.S. and coalition access to Turkish air bases, including the base at Incirlik, according to an administration official.

The decision was disclosed on Thursday, a day after a telephone call between President Barack Obama and Turkish President Tayyip Erdogan, and follows long-time reluctance by Ankara to become engaged in the fight against ISIL fighters.

The authorities say IS members, but also Kurdish militants and Marxists, are among nearly 300 suspected extremists arrested in early morning raids in Istanbul and other cities.

A total of 297 people including 37 foreigners were detained, Prime Minister Ahmet Davutoglu said, adding that the raids took place in 16 provinces across Turkey. One Turkish soldier was killed.

The air strikes hit three targets in the north of country, but the government insists the jets did not violate Syrian airspace.

“This was not a point operation, this is a process”, Davutoglu said.

The private Dogan news agency said as many as 35 IS militants were killed in one of the three targets hit.

“We also heard reports that F16 jets were scrambled over the border area after the attack, although the Turkish government and the military are saying that they are just routine surveillance flights”.

It came after one soldier was killed and two sergeants wounded on Thursday by fire from five I.S. militants on the Syrian side of the border.

Kurdish militants, many of whom blame Turkey for not doing more to stop ISIS, reportedly responded by killing two Turkish police officers.

A suicide bombing blamed on IS killed 32 people in Suruc, a small town in Sanliurfa province on the border with Syria on Monday, an attack widely viewed as being at least partly motivated by the crackdown against IS. Anadolu said Bayuncuk was previously arrested over alleged al-Qaida links and wrote articles for IS publications.

There were violent clashes across Turkey as hundreds of protesters took to the streets to condemn the attack in Suruc and accused the government of not doing enough to combat the threat of IS.

“The slightest movement threatening Turkey will be retaliated against in the strongest way possible”.