Venezuela has announced the arrest of an unspecified number of Americans on charges of espionage, at least some of whom have reportedly been released and left the country. Speaking at a rally, Venezuelan President Nicolás Maduro said the suspects were trying to stoke anti-government political sentiment.

President Nicolás Maduro: “We’ve detected activity, and we have captured some U.S. citizens in undercover activities, in hidden activities, espionage, trying to win over people in towns along the Venezuelan coast, trying to win over people in some neighborhoods. In Táchira, we captured a pilot of a U.S. plane of Latin origin with all sorts of documentation.”

Maduro also announced new restrictions on the number of U.S. diplomats allowed in Venezuela, and rule changes that will subject Americans to the same visa requirements Venezuelans face in the United States. Maduro has also unveiled a list of American politicians barred from entering Venezuela in response to U.S. sanctions against Venezuelan officials last year. Maduro has repeatedly accused right-wing opponents of fomenting a coup with U.S. support. The White House has denied the charges but said last week it’s considering “tools” to “steer the Venezuelan government in the direction … they should be headed.”