The report undercuts months of assertions by senior Trump officials, who have repeatedly claimed they have no power to compel the return of these individuals.

Over 200 migrants who were sent to El Salvador's CECOT mega-prison under accusations that they were members of a violent criminal gang are the responsibility of the United States, the government of El Salvador told a United Nations working group.

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