The Pentagon transferred five Yemenis held at Guantanamo prison to foreign custody on Wednesday in the first handover of detainees in 2015, sending four to Oman and one to Estonia despite Republican calls for a moratorium on the resettlements.
US officials said all five Yemenis, held for a dozen or more years at the military prison at a US Navy base in Cuba, had been cleared for release nearly five years ago by a multi-agency task force that included intelligence, diplomatic and military officials.
The transfer took place just a day after several Republican US senators, including Kelly Ayotte of New Hampshire, proposed legislation to place a moratorium on the release of most of the Guantanamo prisoners, saying they posed too much danger to the United States and its allies.
President Barack Obama has promised to close the internationally condemned detention center, which was opened in 2002 to house detainees in the US campaign against al Qaeda.
His efforts have been blocked by lawmakers who reject the plan, including Senator John McCain, his Republican opponent in the 2008 presidential election, who said this week 30 percent of the released detainees have re-entered the fight against the United States.
Obama recently pledged to step up the closure effort, and the administration moved 28 prisoners from Guantanamo in 2014, the most since 2009.
The transfer on Wednesday leaves 122 detainees still at the facility. Fifty-four of those, including 47 Yemenis, have been approved for resettlement, while the rest are considered too dangerous to release.
The Pentagon identified the detainee sent to Estonia as Ahmed Abdul Qader, about 31, who had been held 12 years at Guantanamo.
Those sent to Oman were Al-Khadr Abdallah Muhammad al-Yafi, about 44, who had been held 13 years; Abdul Rahaman Atah Mahmood Shubatti, about 32 and imprisoned 12 years; Fadil Husayn Salih Hintif, about 33 and imprisoned 12 years; and Mohammed Ahmed Salam, 34, who was detained 12 years.
US officials insisted security had been a top concern in considering the releases.
"We take our obligation to assess the security risk of detainees seriously prior to transfers. As a result, more than 90 percent of detainees transferred during the Obama administration live quietly around the world," said Paul Lewis, the Defense Department's special envoy for closing Guantanamo.
"Each of these five individuals was unanimously approved for transfer more nearly five years ago by six departments and agencies through the 2009 executive order task force," said Ian Moss, a spokesman for Guantanamo issues at the State Department.