The U.S. government used an 18th-century wartime law to deport more than 200 Venezuelan immigrants earlier this month to El Salvador, where they were immediately transferred to the country's maximum-security gang prison.

U.S. Homeland Security Secretary Kristi Noem on Wednesday is expected to visit a mega-prison in El Salvador holding Venezuelans deported by the U.S. as civil rights groups challenge the removals in a high-profile court battle.