President Barack Obama approved Monday the resumption of military trials for detainees at the U.S. prison at Guantanamo Bay, Cuba, ending a two-year ban.

It was the latest acknowledgement that the detention facility Obama had vowed to shut down within a year of taking office will remain open for some time to come.

"I strongly believe that the American system of justice is a key part of our arsenal in the war against al-Qaeda and its affiliates, and we will continue to draw on all aspects of our justice system — including Article III courts — to ensure that our security and our values are strengthened," the president said in a statement. Article III courts are civilian federal courts.

Under Obama's order, Defence Secretary Robert Gates will rescind his January 2009 ban against bringing new cases against the terror suspects at the detention facility.

Closure of the facility has become untenable because of questions about where terror suspects would be held.

Omar Khadr's sentence will not be affected by the U.S. decision to reopen military trials at Guantanamo Bay. (Janet Hamlin/Reuters)

The case will not affect the naval base's only Canadian detainee, Omar Khadr, who was found guilty and sentenced to 40 years in prison by a U.S. military panel in October. Khadr will serve a maximum of eight years because of a pre-trial plea deal, with the first year served at Guantanamo Bay, after which he is expected to be transferred to Canada.

Khadr spends about 18 hours a day in his maximum security cell.

With files from CBC News