A US federal judge on Thursday sentenced a Nigerian man who pleaded guilty to trying to blow up an airliner bound for Detroit to life in prison.

Umar Farouk Abdulmutallab - who became known as "the underwear bomber" - admitted to eight charges including the attempted murder of 289 people on board Northwest Airlines Flight 253.

US District Judge Nancy Edmunds decided that existing sentencing guidelines, stipulating a mandatory life sentence, should stand. Abdulmutallab, who has maintained that his actions were righteous, appeared to show no emotion as the maximum sentences were handed down for each count.

"The defendant has stated and it is clear that he has enormous motivation to carry out another terrorist attack," Edmunds said.

"This court has no ability to control the defendant's motivation, which does appear to be unchanged, however I can control the defendant's opportunity to carry out those actions."

Plea for leniency

Abdulmutallab's lawyer, Anthony Chambers, had asked for a lighter sentence on the grounds that the defendant was not guilty of killing anyone in the attack on Christmas Day, 2009.

The bomb hidden in Abdulmutallab's underwear failed to properly detonate, instead causing a fire as the plane began its descent. Passengers and crew members restrained Abdulmutallab and extinguished the blaze, allowing the plane to land safely.

During the trial, Abdulmutallab claimed he had been carrying a "blessed weapon" to avenge Muslims who have been killed or badly treated throughout the world.

He admitted to having been inspired by US-born Muslim cleric Anwar al-Awlaki, believed to have been al Qaeda's chief of operations in Yemen. Awlaki was killed in a drone attack in Yemen last September.

rc/dfm (AP, AFP, Reuters)