Security concerns have delayed plans to transfer Guantanamo Bay detainees to Yemen, challenging US President Barack Obama's efforts to close the prison.

White House officials said the threat posed by a Yemeni-based al-Qaida offshoot meant that sending the inmates to the Middle East nation was not an option for the foreseeable future, although that could change should conditions improve.

Obama lifted his self-imposed ban on repatriating prisoners to Yemen in May 2013, but his administration has yet to use that authority.