NEW YORK, Oct 3: A Pakistani-American who admitted trying to set off a bomb in New York's Times Square faces sentencing on Tuesday, with prosecutors demanding the man be incarcerated for life.

Faisal Shahzad, a US citizen who lived in Connecticut and started what resembled an ordinary American family before embracing militancy, pleaded guilty in June to the May 1 bombing attempt.

The bomb scare and revelations that the Taliban in Pakistan were behind the attack strained US-Pakistani relations, while deepening worries in the United States about so-called home-grown terrorists.

Shahzad, 30, was defiant in his last court appearance, claiming to have committed the crime in revenge for bombing by US drones in Pakistan.

Prosecutors say he should be shown no clemency.

“Far from providing an explanation for his criminal activity, Shahzad's history and characteristics strongly militate in favour of the maximum available sentence,” assistant US attorney Randall Jackson said in court papers ahead of the sentencing hearing.

The bombing attempt failed when the crude device, left in an SUV parked outside a theatre on a warm Saturday evening, fizzled without igniting.

The entire operation was characterised by extreme amateurishness, with the bomber having to escape on foot because he left the keys to a second getaway car – and those to his apartment – inside the vehicle with the bomb.

But officials say that the bomb, had it gone off, would have caused carnage in one of New York's busiest neighbourhoods.

Last week, FBI officials recreated the device in an empty field to demonstrate the fiery explosion they said could have occurred.

Prosecutors say that Shahzad boasted he expected to kill at least 40 people and that he had also planned to set off a second explosion, had he not been caught.

According to prosecutors, he admitted using Internet webcam sites to monitor Times Square and see when and where a bomb would be most likely to cause bloodshed. The car bomb was discovered smoking by a street vendor who alerted police.

Once the teeming area had been cleared, police dismantled the device and launched a frantic manhunt, catching the bomber 53 hours later, just after he'd boarded a plane to leave from JFK Airport to Dubai.—AFP