Senior White House officials have said that the Pakistani Taliban was behind the failed Times Square car bombing.
The attempt marks the first time the group has been able to launch an attack on US soil.
While US officials have downplayed the threat, some feared the incident in Times Square and the Christmas Day airline bomb attempt indicated growing strength by overseas groups linked to al-Qaida. The finding also raises new questions about the US relationship with Pakistan, widely known to have al-Qaida and other groups within its borders.
Yesterday, suspected US missiles killed 10 people in a militant-controlled region of Pakistan, the first such strike since alleged Pakistani-trained extremist Faisal Shahzad was accused of the Times Square attack.
US Attorney General Eric Holder said that new evidence shows that the Pakistani Taliban was “intimately involved” in the bombing plot. John Brennan, the president's homeland security and counterterrorism adviser, made similar remarks, linking the suspected bomber to the Tehrik-e-Taliban Pakistan, or TTP.
The militant group is believed to be hiding senior al-Qaida leaders, including Osama bin Laden.
“We know that they helped facilitate it,” said Mr Holder. “We know that they probably helped finance it. And that he was working at their direction.”
A US citizen of Pakistani descent, Shahzad is accused of spending five months in Pakistan before returning to the US in February and preparing his attack.
Shahzad was arrested on an Emirates Airlines jet in New York minutes before it was scheduled to take off for Dubai.