Lawyers and activists have raised questions over the nature of the deals with countries in Africa and elsewhere. Several of the African nations that have signed such deals have notoriously repressive governments and poor human rights records — including Eswatini, South Sudan and Equatorial Guinea.

A key bone of contention in many such agreements is that they involve many migrants with protection orders from a U.S. immigration judge not to be returned to their home countries over major safety concerns.