Times Square bomber planned second attack, says US

US prosecutors said on Wednesday they are seeking life in prison for a Pakistani-born American citizen who tried to set off a car bomb in New York's Times Square and revealed he had planned a second attack.

Faisal Shahzad, 30, pleaded guilty in June to the failed bombing on May 1 in busy Midtown Manhattan. He was arrested two days later aboard a Dubai-bound plane, minutes before it was due to leave New York's John F Kennedy International Airport.

Shahzad admitted he received training in bomb-making from the Pakistani Taliban, called Tehrik-e-Taliban Pakistan, and said they had funded the failed attack.

Court documents made public on Wednesday revealed Shahzad had told investigators he thought his bomb would have killed at least 40 people, and that he had planned to carry out a second bombing attack two weeks later. The target of the second attack was not identified in the documents.

Prosecutors said Shahzad, a naturalized US citizen, posed a "particularly pernicious threat" and his prison sentence should deter potential future radicalization of US citizens.

"While it is self-evident that specific deterrence is important in this case, deterring other United States citizens as well as those who are permitted to reside here from working to undermine our national security by aiding foreign terrorist organizations is vital," they said.

Prosecutors also revealed additional details about the plot. They said Shahzad used the internet to study Times Square in a bid to maximize damages. They also said he consulted with militants in Pakistan throughout the bomb-making process.                                           

"Shahzad used the internet to access websites that provided real time video feeds of different areas of Times Square," the court papers said. "These websites enabled Shahzad to determine which areas of Times Square drew the largest crowds and the times when those areas would be most crowded."

As he assembled the bomb from his Connecticut home, prosecutors said, he used specific programs on his computer to communicate with Tehrik-e-Taliban militants.

Shahzad is due to be sentenced in Manhattan federal court on October 5.