BEIJING -- U.S. President Barack Obamahas sought to define his administration’s counterterrorism policies during a speech at the national Defense University.

President Obama has announced new guidelines codifying controversial drone strikes against militant targets, while renewing his pledge to close Guantanamo Bay military detention facility.

Obama said he has signed a Presidential Policy Guidance to codify guidelines, oversight and accountability of drone strikes. He also called on Congress to lift the restrictions on detainee transfers from Guantanamo, while asking the Department of Defense to designate a site in the United Statesto hold military commissions. He will also appoint an envoy to achieve the transfer of detainees to third countries, while lifting the moratorium on detainee transfers to Yemen.

Obama said the change in policy stemmed from the shifting and evolving threat of terrorism to the United States, as al-Qaeda core was on a path to defeat, al-Qaeda affiliates began to emerge, extremists took foothold in countries like Libya and Syriaand home-grown radicalized individuals began to pose real threat.