Eleven more migrants deported by the Trump administration under a policy of sending them to third countries arrived in Eswatini from the United States on Wednesday, a US lawyer following the case said.

The arrivals bring to 29 the number sent to the southern African country under a $5.1-million agreement that has been challenged by lawyers who say deportees are being detained despite having already served sentences for crimes committed in the United States.

Alma David, a lawyer for some of the original deportees sent to Eswatini last year -- and who is in touch with local prison sources there -- confirmed the arrival to Reuters by text message.

Of the 29 deportees sent from the United States to Eswatini, only two have been released and repatriated, one to Jamaica and the other to Cambodia.

An Eswatini government spokesperson did not immediately respond to a request for comment.

The detainees had already been transported to Eswatini's notorious Matsapha correctional facility, David said.

The Trump administration has also deported migrants to other countries in Africa, Asia and the Americas under the policy.