His fellow passengers saw flames coming out of his pants and investigators found explosives sewn into his underwear. So Umar Farouk Abulmutallab's attempt to down a Detroit-bound airliner on Christmas Day 2009 was never much in question.

Still, the 25-year-old Nigerian ended his criminal trial as it was just getting started Wednesday, pleading guilty to eight terrorism charges. He faces a minimum of 30 years in prison when he is sentenced in January.

He wanted to blow up the plane, and kill the nearly 300 people on board, to avenge the deaths of fellow Muslims at the hands of the United States, Israel and other western powers, he said after telling the court he would plead guilty.

"Participation in jihad against the United States is considered among the most virtuous of deeds in Islam and is highly encouraged in the Quran," Abdulmutallab told the court.

The statement is yet another example of a terrorist justifying his actions by invoking radical Islamist ideology. He may have violated American law, he said, but he did not break the laws of the Quran.

"The United States should be warned," he added. "If the United States continues the blasphemy of Muhammad and the prophets and continues to support those who kill innocent Muslims, it should await a great calamity that will befall them at the hands of the mujahedeen soon or God will strike them directly with a great calamity soon. If you laugh at us now, we will laugh at you later in this life and at the day of judgment."