“Panama cannot end up becoming a black hole for deported migrants,” said Juan Pappier, deputy director of Human Rights Watch in the Americas. “Migrants have the right to communicate with their families, to seek lawyers and Panama must guarantee transparency about the situation in which they find themselves.”

Days after the United States sent 300 migrants from Asia and the Middle East to Panama, a Panamanian official said that more than half had agreed to be deported to their countries of origin.

Officials in Costa Rica and Panama are confiscating migrants' passports and cellphones, denying them access to legal services and moving them between remote outposts as they wrestle with the logistics of a suddenly reversed migration flow.

Panama and Costa Rica are among a number of Latin American nations that have agreed to cooperate with U.S. President Donald Trump as he ramps up his deportation machine and restricts access to asylum in the U.