BEIRUT - A bomb blast in a northwestern Syrian town held by Turkish-backed opposition forces killed at least eight people Sunday, activists said, the latest in a series of attacks along the border where Turkey has troops.
The spike in attacks follows Turkish threats to expand its offensive against U.S.-backed Syrian Kurdish forces to the east, where U.S troops are based.
Turkish troops and allied Syrian forces first crossed into Syria in 2016 to drive out Kurdish fighters and Islamic State militants from a swath of territory along the border. Turkey's Syrian allies now administer the region.
Images of the Sunday attack showed small fires and damaged vehicles at a busy market in central Afrin. Vegetables and other merchandise littered the ground, as sirens rang out and rescuers searched for casualties.
The Britain-based Syrian Observatory for Human Rights said the explosion killed eight people and appeared to have been caused by a car bomb. It said the bomb went off in a market near the base of one of the Islamist opposition groups governing Afrin. The activist-operated Shaam news agency reported the same toll.
The Turkish state-run Anadolu news agency said four people were killed and 20 wounded.
Another attack on Thursday killed at least three civilians and one Turkish soldier.
The U.S.-Kurdish alliance has soured relations between Ankara and Washington. Turkey views the main Kurdish militia as an extension of the insurgency within its borders.
The U.S. military has set up observation posts to try to prevent friction between its NATO ally and the Syrian Kurdish militia.
Turkish troops and allied Syrian forces drove the Kurdish militia out of Afrin in March. The majority-Kurdish town has since been controlled by Turkey-backed opposition fighters, but has often come under attack from Kurdish insurgents in the area. The Kurdish militia and affiliated groups complain of a systematic campaign by Turkey's allies to drive out the local Kurdish population.