Turkish ground forces pushed into northern Syria's Afrin province yesterday, Ankara said after launching artillery and air strikes on a US-backed Kurdish militia it aims to sweep from its border.

The Syrian-Kurdish YPG militia, supported by the United States but seen as a terrorist organisation by Turkey, said it had repulsed the Turkish forces and their allies after fierce clashes.

It marked the second day of fighting after Turkey opened a new front in the nearly seven-year-old Syrian war. Under what Ankara has called "Operation Olive Branch", Turkish air strikes on Saturday pounded YPG positions in Afrin.

Turkey sees the YPG as an extension of the outlawed Kurdistan Workers Party (PKK) which has carried out a deadly, three-decade insurgency in Turkey's mainly Kurdish southeast.

President Tayyip Erdogan said his forces would crush the US-backed Syrian-Kurdish YPG militia, saying it could not rely on Washington's support to defeat Turkey.

Erdogan said some of Turkey's allies had provided the YPG with 2,000 plane shipments and 5,000 truckloads of ammunition, comments that appeared to be aimed at US. He vowed to finish Kurdish PKK, PYD, YPG until none are left.

The attacks follow weeks of warnings against the YPG in Syria from Erdogan and his ministers. Turkey has been particularly outraged by an announcement that US planned to train 30,000 personnel in parts of northeast Syria under the control of the YPG-spearheaded Syrian Democratic Forces.

Prime Minister Binali Yildirim said the Turkish military, Nato's second-largest, would create a 30-km (19-mile) "safe zone" in the region, according to broadcaster HaberTurk.

The Turkish military said it had hit 153 targets so far, including shelters and hideouts used by Kurdish militants. The YPG has said Turkey's strikes killed eight civilians and three of its fighters and wounded 13 civilians.

Meanwhile, a missile fired across the border from Syria hit the Turkish border town of Reyhanli yesterday, killing a Syrian national and wounding 32 people, broadcaster NTV reported the town's mayor as saying.

Western governments have largely urged calm, with the US saying the focus should be on fighting Islamic State in Syria. France asked Turkey to act with restraint.

Russia expressed concern over the Turkey offensive. Russian Foreign Minister Sergei Lavrov and US Secretary of State Rex Tillerson discussed the Syrian conflict in a telephone call, in particular ways to bring stability to the country's north, the Russian foreign ministry said yesterday.