SAN SALVADOR, El Salvador (AP) — Lawyers hired by the Venezuelan government filed a legal action Monday in El Salvador aimed at freeing 238 Venezuelans deported by the United States who are being held in a Salvadoran maximum-security prison.

Jaime Ortega, who says he represents 30 of the imprisoned Venezuelans, said they filed the habeas corpus petition with the Supreme Court’s Constitutional Chamber. He said that by extension they requested that it be applied to all Venezuelans detained in El Salvador.

The maneuver essentially compels the government to prove someone’s detention was justified.

The Salvadoran government has been silent about the status of the Venezuelan prisoners since the U.S. government sent them more than a week ago, despite a U.S. federal judge’s verbal order to turn the planes around.

The Trump administration is using an 18th-century wartime law to justify sending the Venezuelans, who it says were members of the Tren de Aragua gang, which the administration declared an invading force.

“We represent at this moment 30 Venezuelans who have given us the power to act, but by extension, we are asking for habeas corpus for the rest of the Venezuelan citizens who are detained in our country,” Ortega said.

Salvador Ríos, another lawyer with the firm, said they were contracted by the Venezuelan government and the Families of Immigrants Committee in Venezuela. He said the Venezuelans they represent are not members of the Tren de Aragua and had migrated from their country and “don’t have any criminal record.”

In February, El Salvador President Nayib Bukele offered to U.S. Secretary of State Marco Rubio to imprison U.S. deportees or even U.S. citizens serving prison sentences. The U.S. is paying El Salvador to hold them for what both governments say is a cost savings.

But lawyers in both countries have questioned the legal justification for sending migrants who have not been convicted or in many cases even charged with a crime to prison in a foreign country.