Current laws “would categorically preclude most U.S. citizens and residents from serving their sentence in El Salvador,” a former U.S. attorney said.

After meeting Secretary of State Marco Rubio, El Salvador's president has offered to house U.S. deportees and even American inmates in his country's "mega-prison."

Under an unprecedented deal reached this week, El Salvador has agreed to accept deportees from the US of any nationality, including violent American criminals.