President Trump’s national security adviser said Sunday that U.S. troops will not be withdrawn from Syria until Turkey guarantees it won’t attack Kurdish forces who have been key allies in fighting against ISIS, according to reports. John Bolton said that Trump, who recently made the abrupt decision to pull some 2,000 U.S. troops from the area, is insisting that Turkish President Recep Tayyip Erdogan commit to leaving Kurdish Syrians alone. Bolton also said this commitment is one of several conditions that must be fulfilled before the U.S. leaves the war-torn region, per NBC News. “There are objectives that we want to accomplish that condition the withdrawal,” Bolton said to members of the press accompanying him on a trip to Turkey and Israel. Bolton’s statement appeared to be an attempt to clarify Trump’s snap proclamation that all U.S. troops would withdraw immediately, and marks a shift in the timetable for withdrawal. He also said that the withdrawal would not remove all U.S. troops from Syria but rather, the majority posted in the country’s northern region. Bolton emphasized, however, that the U.S. will not be in Syria indefinitely. “The primary point is we are going to withdraw from northeastern Syria,” he claimed.