In a filing submitted to a United Nations working group, the government of El Salvador declared that over 200 migrants sent to a Salvadoran prison, amid allegations of gang affiliation, fall under the purview of the United States.

El Salvador's assertion, presented in a legal document earlier in the week, challenges claims by former President Donald Trump and his officials, who persistently argued that the responsibility for these migrants rests with El Salvador, as they are under its jurisdiction.

"In this scenario, accountability and legal jurisdiction over these individuals rest solely with the pertinent foreign authorities as per international treaties, respecting sovereignty and international collaboration in criminal justice," the report by El Salvador to the U.N. elaborated.

These comments were made during a recent legal filing connected to a U.N. Human Rights Office investigation into the disappearance of four Venezuelan men believed to have been sent to El Salvador earlier this year.

As yet, the Trump administration has not disclosed the list of individuals transferred to El Salvador.

In their report, El Salvador officials firmly stated that their authorities have neither detained nor relocated the individuals identified in the U.N. Working Group's report. They clarified that their involvement is limited to facilitating the use of Salvadoran prison facilities for individuals detained by another nation’s justice system.

Under an 18th-century military authority, known as the Alien Enemies Act (AEA), seldom used in modern times, the Trump administration transferred alleged gang-affiliated migrants to El Salvador, citing the Venezuelan Tren de Aragua gang as a "criminal entity" threatening U.S. security.

This transfer to CECOT occurred under an agreement with Salvadoran President Nayib Bukele, intended to accommodate migrant detainees as part of Trump’s broader immigration enforcement policies.

American Civil Liberties Union (ACLU) lawyers challenging the AEA-based deportations — initially questioned in court during the migrants' transfer to CECOT — discovered the filing through communication with the men's families.

The ACLU attorneys criticized the U.S. government for allegedly concealing this information, despite their prior requests for relevant documents concerning the arrangement with El Salvador.

"El Salvador's government has verified what was widely understood: The U.S. governs the situation of Venezuelans at CECOT, bypassing due process," stated Lee Gelernt from the ACLU, reacting to the report sent to the U.N. "It's astonishing that this information wasn't shared with us or the judiciary."

ABC News has sought remarks from the Department of Homeland Security regarding this situation.