A US district court has sentenced Nigeria's ''underwear bomber'' to life in prison for his role in trying to blow up a packed airliner on Christmas Day 2009.

Umar Farouk Abdulmutallab, 25, was handed a mandatory life sentence for attempting to bomb the Detroit-bound Northwest Airlines Flight 253, with 289 people on board.

"As this investigation and prosecution have shown, Umar Farouk Abdulmutallab is a remorseless terrorist who believes it is his duty to kill Americans. For attempting to take the lives of 289 innocent people, he has been appropriately sentenced to serve every day of the rest of his life in prison," Attorney General Eric Holder said.

"Today's sentence once again underscores the effectiveness of the criminal justice system in both incapacitating terrorists and gathering valuable intelligence from them," Holder said in a statement.

The sentencing comes four months after Abdulmutallab of Kaduna, Nigeria, pleaded guilty to all eight counts of a federal indictment.

According to it, in August 2009, Abdulmutallab travelled to Yemen and conspired with al-Qaeda members to bomb an US aircraft over US soil and received an explosive device for that purpose.

Abdulmutallab went ahead with the bomb concealed in his underwear from Yemen to Africa and then to Amsterdam, where he boarded Flight 253 on Christmas Day 2009. The bomb contained PETN and TATP, two powerful explosives, and was designed to be detonated with a syringe containing other chemicals.

His purpose in taking the bomb on board Flight 253 was to detonate it on board, it said.
Fortunately, the bomb failed to detonate and instead simply caused a fire as the plane began its descent to Detroit.