The proposal is almost certainly illegal, experts said, but President Trump’s eagerness to entertain it showed his willingness to embrace extreme measures to demonstrate he is tough on crime.

The Trump administration and the president of El Salvador said they struck a deal allowing the U.S. to ship detained migrants and imprisoned criminals to a mega-prison there.

Salvadoran President Nayib Bukele offered to let Trump move immigrants who are imprisoned in the U.S. to his notorious detention centers in El Salvador.