A Jamaican man deported from the US to Eswatini under President Donald Trump's tough new immigration rules has been sent on to Jamaica, the Eswatini government has said.

Orville Isaac Etoria, 62, was voluntarily repatriated at the weekend, and was warmly welcomed by members of his family, it added.

However, his treatment has been condemned by the Legal Aid Society of New York, which claims Etoria came to the US as a child and had lawful permanent resident status there for decades.

Etoria and four other individuals - from Cuba, Laos, Vietnam and Yemen - were described by the US government as depraved monsters when they were expelled to Eswatini in July.

Since their expulsion, they have been held in solitary confinement in a maximum-security prison in the capital city Mbabane.

Lawyers for the remaining four deportees have stated they have not been able to contact them. Meanwhile, Eswatini's government has expressed its commitment to repatriate all deportees.

Trump's pledge to conduct mass deportations became a central point of his campaign, receiving widespread support. In various situations, individuals have been expelled to countries where they have no connections.

Etoria had allegedly transformed his life after serving a 25-year prison sentence for murder and was reintegrated into American society before being deported and imprisoned again in Eswatini without due process, according to the Legal Aid Society.

Activists in Eswatini have also condemned this deal as unconstitutional, protesting outside the American embassy. Rights groups have initiated legal action to overturn the deal, citing that the government couldn't finalize it without parliamentary approval. The Eswatini government claims to have acted within its authority.

Eswatini, the last absolute monarchy in Africa, has been led by King Mswati III since 1986 and is situated between South Africa and Mozambique.