The government of El Salvador has acknowledged to United Nations investigators that the Trump administration maintains control of the Venezuelan men who were deported from the U.S. to a notorious Salvadoran prison, contradicting public statements by officials in both countries.

The administration in March agreed to pay $6 million for El Salvador to house 300 migrants. The deal sparked immediate controversy when Trump invoked an 18th century wartime law, the Alien Enemies Act, to quickly remove men it has accused of being members of the Venezuelan gang Tren de Aragua.

The revelation was contained in court filings Monday by lawyers for more than 100 migrants who are seeking to challenge their deportations to El Salvador’s mega-prison known as the Terrorism Confinement Center, or CECOT.

The case is among several challenging President Donald Trump’s immigration crackdown.