Pres­i­dent Don­ald Trump on Mon­day re­it­er­at­ed that he’d like to send U.S. cit­i­zens who com­mit vi­o­lent crimes to prison in El Sal­vador, telling that coun­try’s pres­i­dent, Nay­ib Bukele, that he’d “have to build five more places” to hold the po­ten­tial new ar­rivals.

Trump’s ad­min­is­tra­tion has al­ready de­port­ed im­mi­grants to El Sal­vador’s no­to­ri­ous mega-prison CE­COT, known for its harsh con­di­tions. The pres­i­dent has al­so said his ad­min­is­tra­tion is try­ing to find “le­gal” ways to ship U.S. cit­i­zens there, too.

Trump on Mon­day in­sist­ed these would just be “vi­o­lent peo­ple,” im­ply­ing they would be those al­ready con­vict­ed of crimes in the Unit­ed States, though he’s al­so float­ed it as a pun­ish­ment for those who at­tack Tes­la deal­er­ships to protest his ad­min­is­tra­tion and its pa­tron, bil­lion­aire Elon Musk. But it would like­ly be a vi­o­la­tion of the U.S. Con­sti­tu­tion for his ad­min­is­tra­tion to send any na­tive-born cit­i­zen forcibly in­to an over­seas prison. In­deed, it would like­ly even vi­o­late a pro­vi­sion of a law Trump him­self signed dur­ing his first term.