The United States has started sending more migrants deemed by officials to be “high threat” criminal aliens to the U.S. naval base at Guantanamo Bay, Cuba, just days after emptying out the base’s migrant facilities.

Nearly 200 Venezuelan immigrants to the U.S. were returned to their home country after being detained at Guantanamo Bay, in a flurry of flights that forged an unprecedented pathway for U.S. deportations.

The base had been cleared of migrants since Thursday, after the government sent 177 to Venezuela and one back to the United States.