Turkey’s government says it has bombed Islamic State (IS) targets in Syria.
A day earlier the two sides exchanged fire near the border, with one soldier killed and two more injured.
Turkey is to let the US carry out air strikes against the Islamic State group from a key military base near the Syrian border, US officials have said.
Turkish police also launched raids to arrest suspect IS militants on Friday morning in 140 locations in Istanbul.
The raids were carried out in 26 districts of the city and involved 5,000 officers. Members of the the youth wing of the outlawedKurdistan Workers’ Party (PKK) and of a far-left group were also arrested.
The office of Turkey’s Prime Minister, Ahmet Davutoglu, said members of militant groups were arrested in 13 provinces.
The state-run Anadolu news agency said some of the arrests were made in Ankara, Izmir and Sanliurfa province, near the Syrian border.
In a separate statement said Mr Davutoglu’s office said that F-16 jets had hit three IS targets in Syria.
It is the first time Turkey has launched air raids against targets in Syria since IS began its advance through Iraq and Syria in 2013.
Turkish state TV said that the jets had not violated Syrian air space as they attacked the border town of Havar, next to the Turkish town of Kilis.
The US is expected to step up bombing raids against IS after reaching an agreement with Turkey to use the Incirlik airbase.
The agreement was finalised in a phone call between President Barack Obama and his Turkish counterpart Recep Tayyip Erdogan on Wednesday. It was confirmed by US officials speaking on condition of anonymity.
The use of the Incirlik airbase broadens the US military’s ability to strike IS targets – one US official told the New York Times it was a “game changer”.
Once used in raids against former Iraqi leader Saddam Hussein, the base is near to Turkey’s long border with Syria, and significantly narrows the distance to the IS stronghold of Raqqa.