Turkey 'not optimistic' on Syria truce, threatens new strikes

Turkey says it is not optimistic over the implementation of a Syria ceasefire announced by the United States and Russia, threatening to keep up retaliatory artillery strikes against Syrian Kurdish fighters.

"I welcome this truce but I am not very optimistic that it will be respected by all the parties," Deputy Prime Minister Numan Kurtulmus told reporters in Ankara.

He also warned that Turkey could carry on shelling targets of the Syrian Kurdish People's Protection Units (YPG) militia inside Syria, as it did on successive days last week.

Kurtulmus said Turkey will continue "if necessary" to hit back at incoming fire from Syria even after the truce comes into force on February 27.

"Turkey will defend its territorial integrity. That is clear," he added.

Turkey has been alarmed by advances of YPG forces in northern Syria, fearing they are working to create an autonomous Kurdish region on the country's doorstep.

Ankara accuses the YPG and Democratic Union Party (PYD) political wing of being the Syrian branch of the outlawed Kurdistan Workers' Party (PKK) which has waged a decades-long insurgency against the Turkish state.

It also accuses the Syrian Kurdish forces of working alongside Russia, which strongly opposes Ankara's key strategic aim of ousting Syrian President Bashar al-Assad.

Kurtulmus said he had "reservations" about the viability of the ceasefire as he feared Russia would simply continue its air bombardments in Syria.

"We hope that no-one will try and carry out air strikes and that no one is going to kill civilians during the ceasefire," he said.

"We hope that all the groups in Syria, including the moderate opposition, will take part in the reconstruction of the country at the end of negotiations."

The ceasefire deal was announced on Monday by Moscow and Washington but does not apply to the Islamic State group or al-Nusra Front, an al-Qaeda affiliate.

Turkey backs the rebel forces seeking to oust Assad but had repeatedly denied sending illicit deliveries of arms to Islamist fighters across its border.