A car bomb in northeast Syria targeting a checkpoint manned by Turkish-backed forces killed nine people, mostly fighters, near the border town of Ras al-Ain on Thursday, a war monitor said.
The blast in the village of Tal Halaf held by Turkish forces and their Syrian proxies also wounded 15 others, the Britain-based Syrian Observatory for Human Rights said.
Turkish forces and their Syrian proxies last year seized a 120-kilometre (75-mile) stretch of land inside the Syrian border from Kurdish forces, running from Ras al-Ain to Tal Abyad.
Many bombings have since rocked the area, several in the past week alone.
An explosives-rigged motorbike in Ras al-Ain on Tuesday killed two civilians and a fighter, the Observatory said, two days after another in a vegetable market in the town killed eight people, six of them civilians.
The Kurdish-led People’s Protection Units, from whom the Turks and their allies seized the territory, have played a key role in the US-backed fight against the Islamic State jihadist group in Syria.
But Ankara views them as an extension of the Kurdistan Workers’ Party (PKK) that has waged a deadly insurgency in southeastern Turkey since 1984.
Syria’s civil war has killed more than 380,000 people and displaced millions from their homes since erupting in 2011 with the brutal repression of anti-government protests.