WASHINGTON (AP) — A federal appeals court refused Wednesday to lift an order barring the Trump administration from deporting Venezuelan migrants to El Salvador under an 18th century wartime law.

A split three-judge panel of the U.S. Court of Appeals for the District of Columbia Circuit upheld a March 15 order temporarily prohibiting deportations under the Alien Enemies Act of 1798.

Invoking the law for the first time since World War II, President Donald Trump’s administration deported hundreds of people under a presidential proclamation calling the Tren de Aragua gang an invading force.

The Justice Department appealed after U.S. District Judge James Boasberg blocked more deportations and ordered planeloads of Venezuelan immigrants to return to the U.S. That did not happen.

Attorneys from the American Civil Liberties Union filed the lawsuit on behalf of five Venezuelan noncitizens who were being held in Texas.

The case has become a flashpoint amid escalating tension between the White House and the federal courts.

Boasberg, the chief judge of the federal district court in Washington, has vowed to determine whether the government defied his order to turn planes around. The administration has invoked a “state secrets privilege” and refused to give Boasberg any additional information about the deportations.

Trump and his allies have called for impeaching Boasberg. In a rare statement, Supreme Court Chief Justice John Roberts said “impeachment is not an appropriate response to disagreement concerning a judicial decision.”

The Alien Enemies Act allows noncitizens to be deported without the opportunity for a hearing before an immigration or federal court judge.

Boasberg ruled that immigrants facing deportation must get an opportunity to challenge their designations as alleged gang members. His ruling said there is “a strong public interest in preventing the mistaken deportation of people based on categories they have no right to challenge.”

The appeal was heard by Judge Patricia Millett, who was nominated by Democratic President Barack Obama; Judge Justin Walker, was nominated by Trump in 2020; and Judge Karen LeCraft Henderson, who was nominated by Republican President George H.W. Bush in 1990.