5 more detainees transferred from Guantanamo

Five more detainees -- all Yemeni nationals -- were released on Wednesday from the military prison at Guantanamo Bay. For the first time, the tiny Gulf sultanate of Oman will accept four of the men as part of a diplomatic agreement arranged by the State Department. A fifth detainee will be resettled in the Baltic country of Estonia.

It is the latest secret airlift of prisoners conducted in the past two months by the Obama Administration, which is eager to find new homes for prisoners no longer considered a security threat as part of its effort to shut down the facility.

Perhaps most notable is the fact that all of the men transferred are Yemenis who had been held for nearly 13 years yet never charged. The U.S. had banned transfers of Yemenis to Yemen in 2009 after Omar Farouk Abdelmuttab attempted to blow up a plane over Detroit with an underwear bomb as part of an AQAP-linked plot. That al Qaeda offshoot -- al Qaeda in the Arabian Peninsula (AQAP) -- is based in Yemen.

Clearing out the Yemeni prisoners is a major obstacle complicating President Obama's goal of shutting down the military prison. Yemenis make up the bulk of the 122 prisoners who remain at Guantanamo and the majority of them have been cleared for release. U.S. diplomats have been trying to convince other countries to accept those detainees who are no longer considered a security threat.

Key Senate Republicans -- including Senators Kelly Ayotte and Armed Services Chair John McCain -- unveiled legislation this week that would ban transfers to Yemen and effectively block President Obama from fulfilling his campaign pledge to close down Gitmo before leaving office.

Senator Ayotte pointed to a handful of former prisoners suspected of joining AQAP and said there have been "almost 30 percent suspected or confirmed cases of terrorism from those released from Gitmo."

U.S. officials refute those numbers. According to an ODNI report released on Wednesday by the State Department, 19 percent of detainees released during the Bush Administration were "confirmed of re-engaging" in terrorist or insurgent activities. Since the start of the Obama Administration in 2009, those numbers dropped to 6.8 percent. The full ODNI report can be found here.

"We don't just put people on planes and send them out," an Administration official told CBS. The five Yemenis transferred on Wednesday were described as "low level guys at best."

The official explained that all of the prisoners being transferred to Oman and Estonia had been eligible for release since 2010, following an interagency Guantanamo review Task Force review of their cases and security issues.