Turkish planes have for the first time carried out air strikes against Islamic State (IS) group targets in Syria.

Turkish police also raided more than 100 properties in Istanbul, arresting 251 people linked to IS, the office of Prime Minister Ahmet Davutoglu said.

On Thursday, Turkish forces exchanged fire with IS fighters near the Syrian border. One Turkish soldier was killed.

Turkey will now let the US launch air strikes against IS from the Incirlik air base, US officials have said.

The raids in Istanbul alone involved 5,000 officers. Members of the youth wing of the outlawed Kurdistan Workers' Party (PKK) and of a far-left group were also arrested.

The state-run Anadolu news agency said there were also arrests in the cities of Ankara and Izmir and in Sanliurfa province, near the Syrian border.

In a separate statement, 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 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.

This agreement on Incirlik air base goes beyond providing the US-led coalition against IS with a geographical advantage.

Turkey has been in the coalition since from the beginning but was not fully cooperating due to its differing views over the Syrian crisis.

The Turkish government argued that the first priority of an international coalition should be removing President Assad rather than attacking IS. Having the Turkish government clearly backing the coalition brings extra political clout against IS.

The Turkish government, which has until the beginning of this year been accused of turning a blind eye by allowing IS fighters to cross its borders, was under huge international pressure to open the airbase.

The negotiations between the US and the Turkish government came to fruition as recent attacks by IS against Turkish and Kurdish targets added an urgency to the response.

The deal marks a step up in Turkey's involvement in the campaign against IS.

The Turkish government has faced criticism at home and abroad for not doing enough against the extremist group, despite being part of the international coalition fighting IS.

Thursday saw a deadly exchange of fire between Islamic State and Turkey near Kilis.

IS fighters attacked a Turkish border post, with Turkey's army retaliating with heavy weaponry, killing one of the militants.

The incident comes days after the deadly bombing in the predominantly Kurdish town of Suruc, in which 32 people were killed, mostly university students.

The Turkish authorities blamed the attack on IS, with the bomber identified as a 20-year-old believed to have travelled to Syria last year with the help of an IS-linked group.

Kurdish militants said they killed two police officers in the city of Celanpinar as retaliation, accusing the policemen of having collaborated with IS.

Turkey would take "all necessary measures" to protect national security following the attacks, the prime minister's office said.