U.S. Secretary of State Hillary Clinton says the United States expects more cooperation from Pakistan in fighting terrorism and warned of 'severe consequences' if a successful attack in the U.S. was traced back to Pakistan.

In an interview to be broadcast on U.S. television Sunday on the CBS show 60 Minutes, Clinton said Pakistan has significantly increased its military efforts to battle extremists along its border with Afghanistan during the past year.

Clinton said despite Pakistan's recent commitments, the United States wants and expects more.

The top U.S. diplomat said Pakistan had been playing a "double game" in previous years.

U.S. officials have said Pakistani-American Faisal Shahzad, who allegedly tried to detonate a crude car bomb in New York City less than a week ago, has told them he received explosives training in Pakistan.

On Thursday, the Pakistani Taliban denied links to Shahzad.  The group had previously claimed responsibility for the failed attack.  Officials are trying to establish whether Shahzad had connections to foreign terror groups.

In separate comments Friday, U.S. Defense Secretary Robert Gates said the U.S. is ready to offer as much military training and assistance to the Pakistanis as Islamabad is willing to accept.

Gates renewed praise for recent Pakistani army offensives against insurgents, saying the efforts are "much more than any of us would have expected 18 months or two years ago."

Some information for this report was provided by AP and Reuters.