A dozen people were killed and 30 injured in an explosion in a market of a Syrian border town that Turkish-backed forces seized last month, prompting Ankara to blame the Kurdish YPG militia it had targeted in its incursion.
Turkey's state-owned Anadolu Agency said 13 were killed after a "bomb-laden vehicle" exploded.
Tel Abyad is one of two major border towns that saw the heaviest fighting when Ankara launched the incursion on October 9 against the Syrian Kurdish YPG that drew international condemnation. The YPG had for years been a major ally of the United States in the fight against ISIL.
The explosion comes after two weeks of relative calm in northeastern Syria, and a day after Turkish and Russian troops began joint ground patrols under a deal between the two countries that pushed the YPG from Turkey's border.
While Moscow has said the YPG have withdrawn to at least 30 kilometers (18 miles) from the border under the deal, Ankara has been skeptical and held out the possibility of new attacks if members of what it sees as a terrorist group remain.
"We condemn this inhuman attack of the bloody PKK/YPG terrorists who attacked the innocent civilians of Tel Abyad who returned to their homes and lands as a result of the Operation Peace Spring," Turkey's defense ministry said on Twitter.
The Kurdistan Workers Party (PKK), based in Turkey, is designated a terrorist group by Turkey and its Western allies. Ankara considers the YPG a terrorist group because of its ties to PKK Kurdish militants in southeast Turkey.
Turkey's defense ministry published photographs of concrete and debris piled on a street in the town. Anadolu said some of those wounded in the blast were being treated in the Turkish city of Sanliurfa 55 km to the north.
On Wednesday, President Recep Tayyip Erdogan said Turkey had information that the YPG had not completed its pullout from the border region. He has warned that Turkey reserves the right to resume attacks.
