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,

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

On Saturday, President Trump invoked the Alien Enemies Act of 1798 to deport alleged Tren de Aragua gang members. This law has been used three times in U.S. history—during the War of 1812, World War I and World War II.

President Donald Trump on Saturday invoked the Alien Enemies Act for the first time since World War II, granting himself sweeping powers under a centuries-old law to deport people associated with a Venezuelan gang.