Turkish troops killed in Syria as helicopter downed by US-backed Kurdish forces

Two Turkish military personnel were killed on Saturday when a helicopter was downed during Ankara's military offensive against a Kurdish militia in northern Syria.

"At this stage, we can say that one out of two helicopters was downed. We have two martyrs," Turkish Prime Minister Binali Yildirim Yildirim said in televised remarks

"[There was] no evidence (yet) in our hands to prove that it was a result of outside intervention."

Earlier Turkish President Recep Tayyip Erdogan said a military helicopter had been "shot down" over an area which Turkish media identified as the southern border province of Hatay.

Speaking in Istanbul on Saturday, President Recep Tayyip Erdogan didn't mention by name the Syrian Kurdish People's Protection Units [YPG] but said that those responsible will pay for it.

A spokesman for the Kurdish militia, Mustafa Bali, said his fighters downed the chopper in Raju, northwest Afrin.

Turkey resumed airstrikes on Friday in the Syrian Kurdish enclave of Afrin after a brief lull.

Ankara launched Operation Olive Branch in the northern Syrian region of Afrin three weeks ago to fight the Kurdish People's Protection Units (YPG) militia.

Turkey sees this group as an extension of the outlawed Kurdistan Workers Party (PKK).

The PKK is designated as a terrorist group by Turkey, the US and the EU.

But Washington views the YPG as a key ally in the battle against the Islamic State group, and Turkey's offensive this alliance has strained relations between the NATO partners.

Last week, Erdogan announced that 935 "terrorists have been neutralised" in the operation, a figure not yet verified.

Twenty one Turkish soldiers have died since the beginning of the operation.

The UN has estimated that 15,000 people have already been displaced in the offensive, and there are fears that a sustained military campaign could spark a "humanitarian tragedy" for civilians living on the Syrian-Turkish border.