Laurel Miller, United States acting Special Envoy to Afghanistan and Pakistan, has resigned to return to a position at the Rand Corporation.
The U.S. State Department spokesperson Heather Nauert said Secretary of State Rex Tillerson has not yet decided what to do with post.
The office was created when American officials decided that conflicts in Afghanistan and Pakistan are inextricably linked and ought to be dealt with together, the Dawn reports.
Miller's responsibilities will now fall under the department's South and Central Asian Affairs Bureau, which has a much bigger footprint that includes India.
This bureau is also leaderless, with no assistant secretary appointed to lead it and no one nominated by the new administration for Senate approval.
State Department officials are of the view that the decision not to have a special envoy for Afghanistan and Pakistan is part of a broader policy review, and the belief that matters related to these two countries can be handled at the regional level.