The U.S. President Donald Trump invoked the Alien Enemies Act in a proclamation to deport millions of people who are in the country illegally.
He also ordered the removal of hundreds of Venezuelans from the US for their alleged links to a designated Foreign Terrorist Organisation named Tren de Aragua.
The Alien Enemies Act was enacted in 1798 to combat spying and sabotage during tensions with France.
The act requires the president to publicly proclaim the event that prompted the act to be invoked.
The act remains in effect until the president terminates it.