Washington, Jan 9 (DPA) Umar Farouk Abdulmutallab, charged with attempting to blow up a Christmas Day flight over Detroit, pleaded not guilty during his first appearance in federal court Friday.

Abdulmutallab said he understood the charges against him before entering the plea during a very brief arraignment hearing in Detroit at the District Court for the Eastern District of Michigan.

Abdulmutallab, a 23-year-old Nigerian, faces six criminal charges, including attempted use of a weapon of mass destruction. He faces up to life in prison if convicted of the Dec 25 plot, in which he tried, but failed, to ignite explosives as the plane landed in Detroit.

Rod Hansen, the court’s media liaison, described it as a “routine arraignment”. Abdulmutallab spoke quietly, showing little emotion. He spelled his name for the judge, described his education level. His lawyers did not contest him being held in prison until a trial.

Abdulmutallab also acknowledged he was still on painkillers. The suspect had concealed the explosives in his underwear and was treated in hospital after the failed attack.

No dates for the trail or follow-up hearings were set during the arraignment. Abdulmutallab could still change his not-guilty plea, in the hopes of getting a lesser sentence, as the case progresses.

Security was tight outside the courthouse as the case has attracted massive interest. A group of Nigerians from the local community renounced terrorism and showed their support for the US government, the Detroit Free Press reported.

The hearing comes as US authorities try to learn the lessons from the failed attack on the Delta/Northwest Airlines flight, which was prevented only because the PETN explosive that Abdulmutallab smuggled on board failed to properly ignite, instead causing a small fire.

An initial inquiry commissioned by President Barack Obama Thursday found that the intelligence community had “sufficient information” to stop the attack, which was plotted by the terrorist group Al Qaeda’s affiliate in Yemen.

Obama has sharply criticised his intelligence community for the “systemic failure” and outlined a series of measures to strengthen intelligence gathering and analysis. He also detailed stepped up airport security measures, including plans for more full-body scanners, baggage searches and flight marshals.