At least 13 civilians were killed during two separate incidents in the latest flare-up of violence along Syria's northern border with Turkey, the Syrian Observatory for Human Rights, a war monitor, said on Friday.
The bloodshed comes against a backdrop of increased tensions pitting Kurdish-led Syrian Democratic Forces backed by the regime against Turkish forces and their Syrian proxies.
Artillery fire by the Syrian regime on the border town of Al-Bab, which is under the control of Turkish-controlled Syrian forces, killed nine civilians on Friday morning, the Syrian Observatory for Human Rights said.
"Children were among the victims and at least 30 others were wounded," the UK-based Observatory said, adding that the shelling originated from regime positions.
A spokesman for the Kurdish-dominated SDF denied any involvement.
The shelling struck a busy market place, where residents and first responders rushed to assist and evacuate the wounded.
An AFP correspondent said the strike had ripped through the market area and described a jumble of body parts, strewn vegetables and mangled handcarts.
Violence between Turkey and Syria's Kurds escalated this week with a deadly Turkish strike killing 17 regime and Kurdish fighters in retaliation for Kurdish fire inside Turkey.
On Friday, the autonomous Kurdish adminstration in northeastern Syria said an overnight Turkish strike hit a rehabilitation centre for girls in a region near the city of Hasakeh.
The Observatory said four children enrolled in the centre were killed and several others wounded.
Ankara considers the main Kurdish component of the SDF to be a terrorist organisation with organic links to the Kurdish insurgency inside its own territory.
Turkish President Recep Tayyip Erdogan has recently renewed threats of a broad operation against the Kurds in northern Syria but is thought to have failed to secure a green light from Iran and Russia, the two other key foreign brokers in the area.
