President Barack Obama says he is lifting his ban on the transfer of detainees from the Guantanamo Bay, Cuba, detention center to Yemen. And he is calling on Congress to lift its restrictions on detainee transfers, including limits on imprisoning them within the U.S.

In a wide-ranging national security speech, Obama says the Yemen transfers will now be reviewed on a case-by-case basis. The U.S. does not transfer detainees to another country without receiving security assurances, including that those who remain a threat must not be released.

Obama halted all transfers to Yemen after the failed Christmas Day 2009 bombing attempt of an airliner over Detroit. The convicted bomber, Umar Farouk Abdulmutallab, trained in Yemen.

Of the 166 detainees currently at Guantanamo, about 90 are Yemeni.