DUBAI, United Arab Emirates -- Oman said Monday it accepted 10 detainees from the U.S. prison at Guantanamo Bay ahead of President Barack Obama leaving office, part of his efforts to shrink the facility he promised to close.

Oman's Foreign Ministry said in a statement that it had accepted the prisoners at Obama's request. It did not name the prisoners.

"In consideration of their humanitarian situation, 10 persons have been released from detention and arrived in the sultanate today for a temporary residence," the statement said.

The U.S. Defence Department did not immediately respond to questions about the transfer.

A U.S. defence official, speaking on condition of anonymity as the transfer had yet to be publicly announced by the U.S., confirmed the prisoners had been sent to Oman. The official declined to elaborate.

The Omani Embassy in Washington said it had no other information about the transfer. The U.S. Embassy in Muscat declined to immediately comment.

The sultanate of Oman, on the eastern edge of the Arabian Peninsula, previously accepted 10 Guantanamo prisoners from Yemen in January 2016. Oman also took another six in June 2015. Neighboring Saudi Arabia took four prisoners earlier this month and the United Arab Emirates took 15 in the largest-single transfer during Obama's administration in August.

Oman, ruled by Sultan Qaboos bin Said since 1970, has served as an interlocutor between the West and Iran. It also has negotiated a number of prisoner releases in recent years for Western countries.

Yemen, the Arab world's poorest country, remains in the grip of a civil war and a Saudi-led military offensive against the rebels -- making returning Guantanamo detainees there impossible.

Days earlier, authorities said 19 of the remaining 55 prisoners at the U.S. military base in Cuba were cleared for release and could be freed in the final days of Obama's presidency.

Obama has been unable to fulfil promises to close the facility in part because of congressional opposition to transferring any of the detainees to U.S. prisons. Congress ultimately banned the transfer of prisoners to U.S. soil for any reason.

Donald Trump, who will be inaugurated Friday as America's 45th president, said during his campaign that he not only wants to keep Guantanamo open but "load it up with some bad dudes." That's put pressure on the Obama administration to find places to send as many of the prisoners abroad as possible this week.

The U.S. began using its military base on southeast Cuba's isolated, rocky coast to hold prisoners captured during the Afghanistan invasion, bringing the first planeload on Jan. 11, 2002. At its peak, 18 months later, the facility held nearly 680 detainees.

There were 242 prisoners when Obama took office in 2009, pledging to close what became a source of international criticism over the mistreatment of detainees and the notion of holding people indefinitely, most without charge.

A September report released by the Office of the Director of National Intelligence said 122 of 693 detainees transferred out of the prison, or 17.6 per cent, returned to fighting. An additional 86 detainees are suspected of having returned to the battlefield, according to the report.

The majority of Guantanamo prisoners released have been sent to Afghanistan, Saudi Arabia and Pakistan.

Associated Press writer Ben Fox in Miami contributed to this report.