The withdrawal of embassy personnel marks a rapid acceleration of the process that had only been announced on Thursday, and is a situation that many State Department security officials expected would have to happen given the speed with which the Taliban has gained territory in Afghanistan in recent days.

Most of the American diplomats will go to the airport in Kabul and then fly back to the US. A small number of core personnel, including the top US diplomat in the country, will remain at the Kabul airport for now, the sources said. This means that the US Embassy in Kabul will be shuttered — at least for the time being — by Tuesday.