Tren de Aragua (Train of Aragua, or Aragua Train) has roots in Tocorón prison in Venezuela’s northern Aragua state, which the group’s leaders had transformed into a mini-city with a pool, restaurants and a zoo.

In a proclamation, Trump said Tren de Aragua is "undertaking hostile actions and conducting irregular warfare" against the U.S.

The US president had issued an order to deport alleged members of the Venezuelan drug gang Tren de Aragua, arguing he had a right to declare them "alien enemies" under a wartime act.