Belarus declared most U.S. Embassy staff members personae non gratae and ordered them to leave the country.
The United States is one of the fiercest critics of the former Soviet republic's authoritarian president.
The U.S. ambassador left last month after Belarus pulled its ambassador from Washington. The embassy in Minsk, under pressure from authorities, cut its staff by half, reflecting similar cuts made by the Belarusian Embassy in Washington.
Charge d'affaires Jonathan Moore, the top U.S. diplomat in Belarus, said only six officials will remain at the embassy after the latest order.