The suspect in the recent failed car bombing in New York City's Times Square has claimed he visited in a Taliban fighters camp in the Waziristan region.
Hillary Clinton, the US secretary of state, said Washington expects more co-operation from Pakistan in fighting terrorism and warned of "severe consequences" if an attack on US soil were traced back to the South Asian country.
She made the remarks in an interview with CBS television's "60 Minutes" that were to be broadcast later on Sunday.
The US has stepped up its drone attacks on suspected Pakistan Taliban sites after a Jordanian suicide bomber killed seven CIA employees at a US base across the border in the eastern Afghan province of Khost last December.
Pakistan publicly rejects CIA's drone attacks, saying they are a violation of its sovereignty and fuel anti-US feelings, which complicates its efforts against Taliban fighters.
In another development, Pakistani army helicopters attacked suspected fighters' hideouts on Sunday morning in the Shana Garhi area of the Orakzai tribal region, killing at least eight of them, Jahanzeb Khan, a local official, said.
Pakistan security forces are carrying out an operation against fighters who escaped the military offensive in South Waziristan. Some have taken refuge in Orakzai, which lies next to North Waziristan, and other neighbouring tribal areas.