WASHINGTON (AP) — President Barack Obama on Thursday blamed Congress for his failure to keep a promise to close the military prison at Guantanamo Bay, Cuba, saying there’s “simply no justification beyond politics” to keep it open.

Obama pledged when he became president eight years ago to close the facility in his first year, but lawmakers in both political parties blocked the effort.

Obama reduced the number of terrorist suspects being detained on the island from several hundred to 41 as of Thursday in hopes of making a financial case for closing the Bush-era facility. But that argument failed to sway lawmakers, many of whom objected to moving inmates to US prisons on the mainland.

Congress ultimately banned the transfer of prisoners to US soil for any reason.

“The restrictions imposed by the Congress that prevent us from imprisoning detainees, even to prosecute and secure a life sentence, in the United States make no sense,” Obama said in a letter to House Speaker Paul Ryan, R-Wis., dated Thursday, the day before his presidency ends. He noted that no one has ever escaped from a US super-max or military prison.

“There is simply no justification beyond politics for the Congress’ insistence on keeping the facility open,” Obama added, reiterating his argument that continuing to operate the prison jeopardises US relations with its allies and poses a continued threat to US national security.

A few hours after Obama’s criticism of Congress became public, the Pentagon announced that four detainees were being transferred from the facility, three to the United Arab Emirates and one to Saudi Arabia. Earlier this week Oman accepted 10 detainees whom officials had cleared for release.

One of the prisoners sent to the UAE, Ravin Mingazov, was the last Russian citizen held at the base. He had been seeking to resettle in Britain, where he has family.

Donald Trump, who will be sworn in as president on Friday, said during the presidential campaign that he wants to keep Guantanamo open and “load it up with some bad dudes.” That put pressure on the Obama administration to find countries willing to accept as many of the prisoners as possible this week.

Separately, a federal judge in Washington declined Thursday to intervene on behalf of a Moroccan prisoner who had been cleared for repatriation but wasn’t sent home this month because the US said it did not receive required security assurances from his country’s government in time to notify Congress of his release.

Lawyers for Abdullatif Nasser fear he will not be released under Trump and asked US District Judge Colleen Kollar-Kotelly to order that he be freed. She turned back his claim as another judge did in the case of an Algerian prisoner on Wednesday.

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