The failed Times Square car bomber was jailed for life today for trying to bring carnage to crowded central New York.

Pakistani immigrant Faisal Shahzad was told by a judge she hoped he spends some of his time behind bars thinking "carefully about whether the Koran wants you to kill lots of people."

Shahzad's thirst for bloodshed showed no signs of waning as he and Judge Miriam Goldman Cedarbaum sparred repeatedly over his reasoning for giving up his comfortable life in America to train in Pakistan and carry out the potentially deadly attack on May 1.

Instead of exploding, his massive bomb in the back of a sport utility vehicle failed to detonate, attracting the attention of a street vendor, who alerted police. The discovery set off an evacuation of the tourist-laden area and a massive investigation that resulted in his arrest two days later as he sought to flee the country.

"You appear to be someone who was capable of education and I do hope you will spend some of the time in prison thinking carefully about whether the Koran wants you to kill lots of people," Judge Cedarbaum told Shahzad after she announced his mandatory life sentence, which under federal sentencing rules will keep him behind bars until he dies.

Shahzad, 31, responded that the "Koran gives us the right to defend. And that's all I'm doing."

Earlier, Shahzad offered a lecture of his own for Americans, saying he felt no remorse.

"We are only Muslims ... but if you call us terrorists, we are proud terrorists and we will keep on terrorising you," he said.

At another point, he said: "The defeat of the US is imminent."

Judge Cedarbaum said her sentence was very important "to protect the public from further crimes of this defendant and others who would seek to follow him."

During Shahzad's statement, she cut him off at one point to ask if he had sworn allegiance to the United States when he became an American citizen last year.

"I did swear but I did not mean it," said Shahzad, a former budget analyst from Connecticut who was born in Pakistan.

"So you took a false oath," the judge told him.

Shahzad demonstrated throughout the half-hour proceeding in Manhattan that he had not wavered in the months since he pleaded guilty in June to 10 terrorism and weapons counts, some of which carry mandatory life sentences.

"I want to plead guilty and I'm going to plead guilty a hundred times forward," he said in June.

Today he picked up where he left off.

"If I'm given 1,000 lives I will sacrifice them all for the life of Allah," he said at the start of a statement that lasted several minutes and was interrupted several times by the judge who said she wanted to hear what he had to say about his sentencing. "How can I be judged by a court that does not understand the suffering of my people?"

Shahzad, who last year received explosives training in Pakistan to prepare for his bombing attempt, said attacks on Americans will continue until the United States leaves Muslim lands.

"We do not accept your democracy or your freedom because we already have Sharia law and freedom," Shahzad said.

Shahzad had instructed his lawyer not to speak, and smirked as the judge announced her sentence.

Asked by the judge if he had any final words, Shahzad said, "I'm happy with the deal that God has given me."