A federal judge posed a new threat to President Donald Trump’s hardline immigration policies, telling government lawyers he may order the US to facilitate the return of alleged Venezuelan gang members who were deported to a notorious prison in El Salvador.

Despite the judge's order, at least 137 Venezuelans who the administration alleges belong to the Tren de Aragua gang were handed over to authorities in El Salvador, where they are being held in a mega-prison known as the Terrorism Confinement Center, or CECOT. Washington is paying the Central American country's government $6 million to house them.

The ruling, which is limited to the Southern District of Texas, prohibited the administration from using the wartime law because the president’s claims about a Venezuelan gang do not add up to an “invasion.