Three Turkish soldiers were killed in a car bombing in a Turkish-controlled area in northern Syria, Turkeys Defense Ministry said. The ministry said the attack occurred late on Thursday as the soldiers were carrying out road checks in northern Syria, in an area that is under the control of Turkish forces and Turkish-backed Syrian fighters since a Turkish incursion into the region in October. The ministry did not provide further details on the attack. No group immediately claimed responsibility for the bombing. Turkey invaded the border area in neighboring Syria to drive away the Syrian Kurdish Peoples Protection Units (YPG), a group it considers terrorist because of its links to Kurdish rebels fighting inside Turkey. However, the same fighters were the main US allies on the ground in the war against the ISIS group. Thursdays blast was the latest in a series of attacks targeting Turkish troops or the allied Syrian factions in northern Syria. Four soldiers were killed last week in a similar car bomb explosion. More than 20 Turkish soldiers have died in the region since the start of the incursion, which drew widespread international criticism. The United States in turn was seen as abandoning the Syrian Kurdish force that had helped fight ISIS militants.