The Nigerian man accused of trying to blow up a U.S. passenger plane on Christmas Day 2009 has been sentenced to life in prison.

Umar Farouk Abdulmutallab was sentenced Thursday in the U.S. city of Detroit.

U.S. Attorney General Eric Holder called Abdulmutallab a “remorseless terrorist” who deserved to spend “every day of the rest of his life” in prison. U.S. Attorney Barbara McQuade said the outcome shows the civilian justice system can be used effectively to obtain intelligence and convict terrorists.

The 25-year-old Nigerian pleaded guilty in October, as his trial was getting under way. Abdulmutallab had told the court his actions were in retaliation for the killing of what he called innocent Muslims in Yemen, Afghanistan and elsewhere.

Prosecutors say Abdulmutallab wanted to achieve martyrdom by killing all 290 people on board the Northwest Airlines flight as part of an al-Qaida mission.

One of those passengers said she feels the sentence is appropriate.

“His parents – they called me from Nigeria, and they apologized. It broke my heart. And they said, 'my son was misled,' and I believe so, but later on we find out that he had been fully trained by Anwar al-Awlaki, and he was getting training and everything, but he tried to kill us and somehow he missed it. So, in this kind of case, I think justice will be served today, and he will die of imprisonment, and that's what the punishment (will be) for him.”

Passengers and crew members subdued Abdulmutallab after he tried to detonate the explosives in his underwear as the plane prepared to land in Detroit. The explosives caught fire, leaving him with severe burns.

The charges against him included conspiracy to commit terrorism and attempted use of a weapon of mass destruction for trying to bring down the flight from Amsterdam on December 25, 2009.

Abdulmutallab had made several outbursts during jury selection, proclaiming allegiance to al-Qaida and claiming that Yemen-based radical cleric Anwar al-Awlaki is still alive. The American-born Awlaki was killed last year in Yemen by a U.S. airstrike.

U.S. officials have blamed Abdulmutallab's plot on the Yemen-based branch of al-Qaida.