Shortly before the holidays, President Obama was asked whether the detention facility at Guantanamo Bay will be closed by the end of 2015. He didn’t answer directly, but he committed to doing “everything I can to close it.”

The Obama administration’s steady transfer of Guantanamo Bay prisoners continued Wednesday when five detainees were released from the facility and relocated. Congress was notified of the transfer and the administration’s Guantanamo Review Task Force unanimously approved the move, the Pentagon said. The Defense Department announced the transfer of five detainees – one to Estonia and four to Oman. Akhmed Abdul Qadir was transferred to Oman; Al Khadr Abdallah Muhammad Al Yafi, Fadel Hussein Saleh Hentif, Abd Al-Rahman Abdullah Au Shabati and Mohammed Ahmed Salam were transferred to Estonia, according to the Pentagon.

From January to October of last year, just six detainees were transferred from the prison. There’s been a flurry of activity since, and with these new transfers, Guantanamo’s population will drop to 122 detainees, down from its peak of 680 prisoners in 2003

The steady reduction is legal under the policy dictated by Congress – lawmakers won’t let the Obama administration try suspected terrorists in American courts or imprison the detainees on American soil, but there’s nothing stopping U.S. officials from transferring prisoners to other countries once they’ve been cleared for release.

There is, however, a new Republican effort underway to tighten the law and restrict the White House’s options.

Key Senate Republicans on Tuesday unveiled legislation that would effectively block President Barack Obama from fulfilling his pledge to close the U.S. military prison at Guantanamo Bay, Cuba, before he leaves office in two years. The legislation from Sens. Kelly Ayotte, John McCain, Richard Burr and Lindsey Graham would prohibit for two years the transfer to the United States of detainees designated medium- or high-risk. It would also ban transfers to Yemen, where dozens of the 127 remaining Guantanamo detainees are from.

McCain, of course, used to be one of the more notable Republican supporters of closing the Guantanamo facility, even making this part of his 2008 presidential platform.

The Arizona Republican hasn’t officially changed his mind, though. Rather, at this week’s press conference, he simply condemned the Obama administration for failing to present “a concrete or coherent plan” to close the prison that Congress won’t allow the president to close.

McCain, Politico reported , has thrown his support “behind the bill that would tie Obama’s hands on Guantanamo,” even though that would seem to move U.S. policy further away from the goal McCain claims to support.