Turkey has pounded positions belonging to the Islamic State (Isis) and PKK in Iraq and Syria in the second round of airstrikes.

At least 35 militants are thought to have been killed when Turkish warplanes bombarded the IS targets in Syria.

The Turkish F-16s took off from their airbase late on 23 July and returned to the Diyarbakir base, in southeastern Turkey, at about 2am local time. About 20 warplanes were part of the raid.

In the northern Iraq raid, which targeted training and weapons storage facilities, the fighter jets attacked at least five camps of Zap, Basyan, Gare, Avashin and Metina operated by the extremist Kurdistan Worker's Party (PKK).

Aerial strikes have been stepped up following the recent increase in violence in the Syria-Turkey border region. The airstrikes were accompanied by heavy shelling by the ground forces.

"At around 23:00 [20:00 GMT] tonight, Turkish warplanes started bombing our positions near the border, accompanied by heavy artillery shelling," PKK spokesperson Bakhtiar Dogan told the AFP news agency. The PKK, which is banned in Turkey, operates several training camps in nearby Kurdish areas and has a strong presence.

Turkey's state-run Anatolia has confirmed all the jets have returned to safety after the bombardment.

"Whether Ankara likes it or not, after a long period of hesitation and ambiguous posturing, Turkey has been dragged into the fight," columnist Joost Lagendijk wrote in Today's Zaman.

Turkey has long been reluctant to participate in the anti-IS offensive. However, this position has changed in the last few days after Turkey and the US agreed to boost cooperation against the extremist groups in the conflict region.

The country's foreign ministry said in a statement: "The cabinet of ministers has given approval for the stationing in our country's bases of manned and unmanned aircraft of the US and other coalition countries... taking part in air operations against Islamic State."

In addition to the airstrikes, hundreds of suspects linked to the IS and PKK have also been arrested inside the country.