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.

In response to UN inquiries, Salvadoran authorities denied past US claims and stated that they have only facilitated the use of their infrastructure

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,