Two prominent legal groups asked a federal judge Monday to force officials in the Trump administration to explain under oath whether they violated the judge's court order temporarily barring deportations by removing more than 200 people from the U.S. after the order was issued.

The request was the latest salvo in a high-stakes legal fight that began when President Donald Trump invoked a rarely used 1798 wartime law to remove immigrants over the weekend. It also marked an escalation in the battle over whether the Trump administration is flouting court orders that have blocked some of his aggressive moves in the opening days of his second term.

On Saturday night, District Judge James E. Boasberg ordered the administration not to deport anyone in its custody over the newly-invoked Alien Enemies Act, which has only been used three times before in U.S. history, all during congressionally-declared wars. Trump issued a proclamation that the law was newly in effect due to what he claimed was an invasion by the Venezuelan gang, Tren de Aragua.

Trump's invocation of the act could allow him to deport any noncitizen he says is associated with the gang, without offering proof or even publicly identifying them. The plaintiffs filed their suit on behalf of several Venezuelans in U.S. custody who feared they'd be falsely accused of being Tren de Aragua members and improperly removed from the country.

Told there were planes in the air headed to El Salvador, which has agreed to house deported migrants in a notorious prison, Boasberg said he, and the government, needed to move fast. “You shall inform your clients of this immediately, and that any plane containing these folks that is going to take off or is in the air needs to be returned to the United States,” Boasberg told the government's lawyer Saturday night.