Turkish Defence Minister Ismet Yilmaz denied a report that some Turkish soldiers had entered Syria at the weekend and said Ankara was not considering sending troops into its neighbour, the state-run Anadolu Agency reported on Monday.

Syria's government had said Turkish forces were believed to be among 100 gunmen who entered Syria on Saturday with 12 pick-up trucks mounted with heavy machine guns, in an operation to supply insurgents fighting Damascus.

"It is not true ... There is no thought of Turkish soldiers entering Syria," Yilmaz told a Turkish parliamentary commission when asked about the allegation by the Syrian foreign ministry, made in a letter to the UN Security Council.

Turkey's army shelled Kurdish YPG militia targets in northern Syria over the weekend, after the group seized an air base north of Aleppo, further complicating the conflict on Nato-member Turkey's southern border.

Ankara regards the YPG as a terrorist organisation and an extension of the Kurdistan Workers Party (PKK), which has fought a 31-year-old insurgency for autonomy in southeast Turkey. Washington, which does not see the YPG as terrorists, backs the group in the fight against Islamic State in Syria.

Prime Minister Ahmet Davutolgu has demanded that the YPG withdraw from areas it has captured from Syrian rebels.

US President Barack Obama urged Russia on Sunday to stop bombing "moderate" rebels in Syria in support of its ally President Bashar Al-Assad, a campaign seen in the West as a major obstacle to efforts to end the war.

Yilmaz also denied reports that Saudi Arabian aircraft had arrived at Turkey's Incirlik air base for the fight against Islamic State militants, but said a decision had been reached for Saudi to send four F-16 jets.

A Turkish soldier was killed on Sunday evening after Turkey's security forces clashed with a group at the Syrian border that was trying to enter Turkey illegally, the armed forces said in a statement. -Reuters