Clashes in Syria's Afrin intensify as US urges 'restraint'

The Turkish army on Tuesday engaged in intense clashes with Kurdish militia inside Syria as the United States voiced concern over Ankara's military operation in the war-torn country.

Turkey on Saturday launched operation "Olive Branch" aimed at rooting out the Kurdish People's Protection Units (YPG) militia, which Ankara sees as a terror group, from its Afrin enclave in northern Syria.

Dozens of people have been killed in the campaign, the Syrian Observatory for Human Rights said, including 38 Kurdish fighters from the Syrian Democratic Forces (SDF), which is mostly manned by the YPG component. 

Another 43 fighters from pro-Ankara rebels fighting with Turkish forces have also died.

The civilian death toll rose to 28 over three days, the Syrian Observatory for Human Rights said. Two died as a result of Kurdish fire, while the rest were killed in Turkish shelling and airstrikes.

A Turkish soldier was killed Monday on the third day of the offensive, the first Turkish military fatality of the operation.

Sergeant Musa Ozalkan, 30, was laid to rest Tuesday with full honours in a ceremony attended by the Turkish leadership including Erdogan.

A second Turkish soldier was killed in Syria on Tuesday in clashes with the YPG, the military said in a statement. He was named as First Lieutenant Oguz Kaan Usta.

Earlier, a spokesman for the Syrian-Kurdish YPG military said Turkish shelling killed three people in the Syrian town of Ras al-Ayn.

The offensive against the YPG is fraught with diplomatic sensitivities, with Western capitals particularly concerned that it will take the focus away from eliminating IS.

In his strongest comments yet on the offensive, US Defence Secretary Jim Mattis called for Turkey to show "restraint".

He warned the offensive "disrupts what was a relatively stable area in Syria and distracts from the international effort to defeat" IS, on a visit to Indonesia.

France and the European Union have made similar comments to those made by Mattis.

Ankara has expressed impatience with such sentiments, arguing that the YPG is the Syrian offshoot of the Kurdistan Workers' Party (PKK) which has waged a bloody three-decade insurgency against the Turkish state.

The foreign ministry of Qatar - Turkey's closest Gulf ally - gave its unequivocal backing to the operation.

Kurdish call to arms

Syrian Kurdish leaders on Tuesday called on civilians to take up arms to defend the Afrin enclave against the Turkish assault, now in its fourth day.

"We announce a general mobilisation and we invite... our people to defend Afrin," the Kurdish enclave's autonomous administration said in a statement.

Its spokesman Rezan Hedo told AFP: "It is an invitation for all Kurds in Syria to take up arms."

He said the Syrian Democratic Forces, a US-backed alliance dominated by the Kurdish People's Protection Units (YPG), was "ready to receive all those who wish to defend Afrin and provide them with weapons".

The statement called on the international community to assume its "moral responsibility" and urged the UN Security Council to adopt "a firm and serious resolution preventing the Turkish government's aggression on Afrin".

Afrin is one of three autonomous cantons set up in areas under Kurdish control.

The other two - Euphrates and Jazira - are in the main contiguous area of Kurdish control further east.