WASHINGTON (Reuters) - The number of U.S. troops at Kabul airport has fallen below 4,000, a U.S. official told Reuters on Saturday, down from a peak of 5,800.

       The official, speaking on condition of anonymity, added that a drone strike on Friday targeting an ISIS-K planner was not believed to have hit a senior militant and future military operations were possible.

       (Reporting by Idrees Ali; Editing by Daniel Wallis)