The detainees, both ethnic Uighurs, had been ordered freed by a federal judge several years ago on the ground that, although captured in Afghanistan, they were not enemies of the United States.
“We’re just happy for them both,” said Sabin Willett, a Boston-area lawyer who helped represent both men at various stages of their habeas corpus lawsuits.
The United States government did not identify the men, but Mr. Willett said they were Ahmed Mohamed and Abdul Razak. Mr. Mohamed wants to become a salesman or merchant in El Salvador, Mr. Willett said. He said he did not know Mr. Razak’s plans, having never spoken in person with him.
The Bush administration sent 22 ethnic Uighur prisoners from Afghanistan to Guantánamo about a decade ago. Five were released to Albania in 2006, but after a judge ordered the remaining 17 released in 2008, the United States government struggled to find a place to send them.
They could not be repatriated, out of fears that the Chinese government, which is suppressing a separatist movement among Uighurs in the Xinjiang region, would abuse them. China, which had demanded custody, pressured other countries not to take the men.
Early in 2009, the Obama administration came close to resettling several Uighurs in the United States, but dropped those plans after a political uproar.
Bermuda, Palau and Switzerland took in most of the other Uighurs, but five detainees rejected offers to resettle in the countries that had offered to accept them, Maldives and Palau. The three Uighurs who still remain rejected going to El Salvador as well, according to two people with knowledge of the matter.
Mr. Willett said Salvadoran officials interviewed Mr. Mohamed and Mr. Razak at Guantánamo more than a year ago. At one point, the two detainees grew frustrated and fired their legal team, although the lawyers continued to help informally in interactions between them and the government.
The transfer leaves 169 detainees at the prison in Cuba, but the Obama administration notified Congress several days ago that it intended to repatriate one of them, Omar Khadr, a Canadian detainee who pleaded guilty in 2010 to war crimes, according to an American official familiar with the matter.
Mr. Khadr’s plea deal had suggested that he would be transferred to Canada late last year to serve out his sentence — and possibly be paroled — but his request faced bureaucratic delays on both sides of the border. A Canadian government official said this week, however, that the United States had formally asked it to take Mr. Khadr back and that all that remained to be worked out was the timing.