The State Department didn’t respond to multiple requests for comment, but there is no indication that it has raised the issue as part of the talks....

One of those, Liberia, refused 85 criminals’ return, even as the U.S. was providing extensive help to combat an Ebola outbreak.

Among them, Guatemala, Honduras and El Salvador refused 127 criminals and 145 noncriminals in 2014.

The Guatemalan and Honduran embassies didn’t respond to repeated messages requesting comment, but El Salvador’s embassy in Washington said it does what it can while guaranteeing that its citizens go through legal due process.

“We want to make clear that there’s no policy that allows refusing deportations. On the contrary, our consulates give assistance to all Salvadoran prisoners in the United States seeking to facilitate their return to the country, where many of them won’t be in prison,” said Ana Virginia Guardado, an embassy spokeswoman.

She said her country refused return in cases in which the individuals rejected El Salvador’s consular help. She said El Salvador is still working on those cases and that individuals will be given travel documents allowing their deportation once they have exhausted all of their legal avenues in the U.S.

She said El Salvador has worked to accept nearly 8,000 deportees so far this year....

Ms. Rodriguez said the number of refusals from the Central American countries is low compared with the total number of deportations. El Salvador’s 2014 refusal rate was less than half of a percent of the total number who were accepted back.

She said the cases that are refused often have special circumstances that make them tougher to complete. Even after they are released, however, the Zadvydas cases are still in the system and ICE is still working to deport them as soon as possible.