A young Nigerian man pleaded guilty on Wednesday to trying to kill nearly 300 people aboard a US-bound airliner on Christmas Day 2009 by igniting explosives in his underwear.
"Do you understand that you have the right to remain silent?" judge Nancy Edmunds asked the 25-year-old Umar Farouk Abdulmutallab, who fired his own lawyers and is representing himself at the trial in Detroit, Michigan.
Abdulmutallab, wearing a blazer over a collarless shirt, his hands clasped in front of him, replied "Yes."
"Do I understand correctly that you wish to waive that right to plead guilty to all the charges in the indictment?" asked the judge.
"Yes," again came the reply, this time met with gasps of shock from the gathered media.
Edmunds read through each of the eight terrorism-related charges. Each time, Abdulmutallab said "I plead guilty," and when asked by the judge whether he was was pleading guilty because he "was guilty," the accused said "that's right."
The surprise guilty pleas come a day after Abdulmutallab declined to present opening statements to jurors.
"Has anyone promised you that I would go easy on you if you pleaded guilty?" asked Edmunds. "No," the Nigerian replied.
The plot, which US officials say was the work of al Qaeda in the Arabian Peninsula, failed because the explosives stitched in his underwear never detonated fully and instead caused a massive fireball.
That fireball could have been deadly but for the swift actions of passengers and crew members who rushed over to put it out as panic and pandemonium broke out on the Northwest Airlines flight from Amsterdam as it prepared to land in Detroit, the prosecution says.
The botched operation triggered global alarm and led the United States to adopt stringent new screening and security measures, including controversial pat-downs at airports and a massive expansion of the no-fly list.
The reputation of the nation's intelligence services also took a hit because Abdulmutallab's father, a prominent Nigerian banker, had warned the CIA about his son's growing radicalization.
Abdulmutallab's calm and respectful demeanor on Wednesday was in sharp contrast to his disruptive behavior during jury selection.
This was marked by incendiary outbursts, including a pledge that militants will wipe out "the cancer US," and praise for radical al Qaeda cleric Anwar al-Awlaqi and former leader Osama bin Laden, both killed in US raids.
Abdulmutallab faces life in prison for the terrorism-related charges he pleaded guilty to.