Turkey and Iraq's autonomous Kurdish region have warned that they will consider any violent group that abuses a Syrian power vacuum a "common threat", in a reference to Kurdish rebels in Syria.

"The new Syria should be free of any terrorist and extremist group or organisation," Turkey's foreign minister Ahmet Davutoglu and Iraqi Kurdish leader Masoud Barzani said in a rare joint statement released late Wednesday.

The statement comes after the pair held talks in the northern Iraqi city of Arbil over the situation in Syria and reports that some parts of the country had fallen to the Kurdish rebels.

"Any attempt to exploit the power vacuum by any violent group or organisation will be considered as a common threat," said Barzani and Davutoglu in their joint statement.

Davutoglu was visiting the oil-rich city of Kirkuk on Thursday, Turkish media reported, adding that the foreign minister would bring together Syrian opposition groups.

The Democratic Union Party (PYD), the Syrian ally of the outlawed Turkish Kurdistan Workers' Party (PKK), had allegedly seized control of several towns along Turkey's border with Syria, alarming Ankara, which promptly increased defences on the border.

Turkey's Prime Minister Recep Tayyip Erdogan said last week Ankara would not hesitate to strike Kurdish rebels in Syria.

Ankara claims some of the Kurdish rebels in Syria are those who have been forced to move from their hideouts in mountainous zones in northern Iraq, after Turkey staged several air strikes in the area to drive out the rebels.

A military drill close to the Syrian border and an increase in the firepower deployment on the border followed the movement in northern Syria.

Ankara had already fortified the border region after a Turkish plane was brought down by Syria on June 22.

The PKK took up arms in Kurdish-majority southeastern Turkey in 1984, sparking a conflict that has claimed some 45,000 lives.