President Donald Trump declared on Saturday that the United States is being invaded by the Venezuela-based gang Tren de Aragua and ordered for the deportation of all members of the gang who are residing in the country illegally.

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.

The United States has deported hundreds of alleged members of the Venezuelan gang Tren de Aragua using the Alien Enemies Act, now blocked for 14 days by a federal judge. El Salvador has received these individuals for confinement.