President Donald Trump used wartime authority to deport nearly 240 alleged Latin American gang members to a mega-prison in El Salvador over the weekend. A federal judge unsuccessfully sought to block the administration’s actions,

Tren de Aragua, a gang born out of a Venezuelan prison, is a loose network that doesn’t operate like groups typically considered terrorist organizations.

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.