Venezuelan President Nicolas Maduro said on Saturday his government had detained American citizens including a pilot on suspicion of espionage, in a move likely to strain already tense relations between Washington and Caracas.

Maduro also said his government would order a reduction in the number of staff at the United States embassy in Caracas and prohibit some U.S. officials from entering Venezuela in retaliation for a similar U.S. measure last year. Venezuela would also require U.S. citizens to obtain visas before visiting, he told a rally.

The Venezuelan president, long at odds with Washington, has renewed accusations in recent weeks that the United States is seeking to topple him.