Debates over President Donald Trump’s hardline migration policies are focused on the Venezuelan gang Tren de Aragua, to some a ruthless transnational criminal organization and to others the pretext for an overhyped anti-migrant narrative.

(CNN) — The Trump administration has sparked controversy with its move Sunday to deport 261 people, some of whom it alleges are members of the Venezuelan gang Tren de Aragua, to an infamous maximum-security prison in El Salvador.

The deportation of 261 Venezuelans, including suspected members of the gang, was carried out on Saturday. By the time a federal court halted the move, two planes carrying immigrants had already left the country.