Eight civilians were killed and 35 injured in one mortar strike in Nusaybin in Mardin province, according to the governor's office cited by local media.

Two others died when a shell hit a house in the town of Suruc, adjacent to Kobane in Syria, the Anadolu news agency reported.

That took the total civilian death toll to 17 since cross-border shelling by Kurdish militants began on Thursday, with dozens more injured.

Ankara launched "Operation Peace Spring" on Wednesday against the Syrian Kurdish People's Protection Units (YPG), which it considers a "terrorist" off-shoot of Kurdish insurgents in Turkey.

Two Turkish soldiers were killed and three injured in direct fighting with the YPG in northeastern Syria on Friday, the defence ministry said.

The other two died after a shell hit a military base in Azaz further west, beyond the zone of the current offensive, according to state news agency Anadolu.

Violent clashes have taken place primarily around the Syrian border towns of Tal Abyad and Ras al-Ayn, which are controlled by the YPG.

The Syrian Observatory for Human Rights said 41 fighters for the YPG-led Syrian Democratic Forces have been killed since the operation began.

Kobane was the site of a major months-long battle in 2014 and 2015 by Kurdish forces to retake the town from the Islamic State group.