According to sources, detainees held at the U.S. prison complex in Guantanamo Bay, Cuba, can not be sent to Yemen after the Obama administration effectively reinstated a ban on such transfers given the volatile security situation in the Arab world's poorest country.

The Associated Press sources report that as part of his efforts to close the prison, President Barack Obama approved the option of repatriating prisoners to Yemen nearly two years ago, but while former detainees have ended up in places as unlikely as Uruguay and Slovakia, the Yemeni option has so far remained entirely theoretical.

Yemen is home to "al-Qaida in the Arabian Peninsula," an offshoot of the terror organization that U.S. intelligence experts consider the most dangerous branch. The group claimed responsibility for the attack on the French satiric newspaper Charlie Hebdo, as well as a number of failed strikes against the United States.

In recent months, Yemen has further been gripped by a violent power struggle that turned Shiite rebels against both al-Qaida and the central government in the capital of Sanaa. The militants, known as Houthis, this week managed to take President Abed Rabbo Mansour Hadi prisoner in his own home.

Obama insisted in his State of the Union address on Tuesday he still plans to shut down the Guantanamo detention center before he leaves office, but the president's plans are complicated by the fact that nearly two-thirds of the 122 remaining prisoners are Yemeni nationals; 47 of them have been approved for transfer.

The administration is now reportedly working with other countries to assess where the detainees might be sent.

Meanwhile, Republicans in Congress would like to cement the end of Yemeni transfers by passing legislation that reinstates a formal ban on the practice.

"The last thing we should be doing is transferring detainees from Guantanamo to a country like Yemen," said Sen. Kelly Ayotte, a Republican from New Hampshire. "We have not received assurances from the administration that they will not seek to transfer anyone to Yemen, despite the wild, wild West nature of what we're facing when it comes to terrorism in Yemen."