Kurdish forces in northern Syria have arrested a Portuguese extremist from London involved in kidnappings and executions of Western hostages held by ISIS after years on the run.

Government airstrikes and artillery attacks ceased Saturday following a unilateral cease-fire in the northwestern province of Idlib, a Syrian war monitor said. The U.S. military, meanwhile, said it struck an al-Qaida leadership facility north of Idlib, marking the first American strike inside the war-torn country since July .

The Taliban claimed responsibility for an explosion in Kabul late Monday, just hours after a U.S. negotiator shared with Afghan President Ashraf Ghani “key details” of a deal that would see thousands of American troops leaving Afghanistan.