It comes at a time when evidence about Pak Taliban's involvement in New York bomb plot has emerged.
Group 'facilitated, financed' Faisal Shahzad's bombing attempt in New York's Times Square.
However, US Attorney General says Pakistani government was not aware about the plot.
US wants urgent action against Islamic militants following last week's Times Square car bombing in New York.
Pakistani American Faisal Shahzad had visited South Waziristan, a stronghold of the Pakistani Taliban. But did he have links with the militant group?
After Times Square, the US is reviewing the process of granting citizenship and call it the Shahzad Faisal effect.
The US State Department has taken note of multiple plots involving American and Pakistani citizens.
If a terror operation like the Times Square attempt were to be successful there would be severe consequences.
It says Shahzad was a close childhood friend of one of the alleged masterminds of the Mumbai carnage.
Faisal Shahzad's involvement with Pak militant group could range from training to communication.
Pakistan-origin Faisal Shahzad, was arrested for parking an explosive-laden vehicle at Times Square this week.
Pakistani investigators are also probing Shahzad's possible connections with Jaish-e-Muhammad.
Pakistan has confirmed that Faisal Shehzad did meet Taliban leaders in 2009.
Pakistan has condemned the failed bombing attempt at New York's Times Square by Faisal Shahzad.
Faisal Shahzad has reportedly told the FBI that he acted alone, but his motives are not clear.
Faisal Shahzad, the man who tried to bomb New York's Times Square, just minutes before he was to take off from the US.
The 30-year-old suspect, Faisal Shahzad, is the son of a retired official in Pakistan's air force.
Pakistan and the US are working together to ensure Pakistan is not being used for an act of terrorism.
The alleged bomber has admitted to receiving training in Pakistan while two others are arrested in Pakistan.