New Orleans, Louisiana - A US federal appeals court ruled Tuesday against President Donald Trump's use of a wartime law to deport people accused of being Venezuelan gang members and blocked its use in some southern states.

Trump first invoked the 1798 Alien Enemies Act (AEA) on March 15 and flew two planeloads of persons it accused of being Tren de Aragua gang members to El Salvador's notorious maximum security CECOT prison.

The centuries-old law – last used to intern Japanese-American citizens en masse during World War II – has since been targeted in a series of legal challenges.

The Fifth US Circuit Court of Appeals delivered a 2-1 ruling on Tuesday saying Trump could not rely on the law to deport migrants in Texas, Louisiana, and Mississippi.

Donald Trump Trump brutally strips nearly half a million federal workers of their union rights

Politicians MAGA congressman claims Ghislaine Maxwell "exonerated" Trump in DOJ testimony

"We conclude that the findings do not support that an invasion or a predatory incursion has occurred," wrote judge Leslie Southwick.

"We therefore conclude that petitioners are likely to prove that the AEA was improperly invoked."

The Act allows the government to detain and deport citizens of hostile foreign nations in times of war or during an "invasion or predatory incursion."

Southwick, with judge Irma Carrillo Ramirez agreeing, granted a preliminary injunction blocking removal.

Judge Andrew Oldham dissented, saying it depended on "matters of political judgment" to determine whether AEA's preconditions were met.

Robert F. Kennedy Jr. Prominent RFK Jr. critic who called him a "dangerous man" axed from FDA vaccine committee

Politicians Gavin Newsom rips JD Vance over eyeliner and past hatred for Trump: "Grew a beard and lost his spine"

"From the dawn of our nation until President Trump took office a second time, courts have never second-guessed the President's invocation of that Act," Oldham wrote.

Legal challenges to Trump's use of the AEA are expected to eventually reach the Supreme Court.

Trump unprecedented mass deportation campaign has encountered pushback from judges across the country.

Another US federal appeals court last week temporarily blocked the Trump administration from stripping temporary protected status from some 600,000 Venezuelans living in the US.