Pakistan's government has promised to co-operate with the investigation into the failed car-bomb attack in Times Square, which has uncovered possible links to the Pakistani Taliban and an Islamist group in Kashmir.
Pakistani Interior Minister Rehman Malik said the US had made a formal request to Pakistan to investigate links between the main suspect, Faisal Shahzad, and militants in the north-west.
"They think that Shazhad had been visiting South Waziristan and meeting [Taliban leaders] Qari Hussain and Hakimullah Mehsud. But it all needs confirmation," he said on Saturday.
Mr Shahzad, who was born in Pakistan and became a US citizen last year, has been charged with terrorism, attempting to use a weapon of mass destruction. He has yet to appear in court.
Prosecutors say Shazhad is continuing to co-operate with investigators, and has admitted to receiving bomb-making training Waziristan.
ABC News has reported that Mr Shahzad told investigators he was angry because friends had been killed by CIA strikes in Pakistan, his personal life was in crisis, and he feared for the safety of his family.
How Times Square bomb suspect was arrested
The trail which led to the arrest of Times Square bomb suspect began
with the discovery of a suspicious car early on Saturday evening, 1 May, close to New York's busy Times Square.
The Nissan Pathfinder was caught on cctv cameras arriving in Times
Square just before 1830 EDT. A street seller raised the alarm when he noticed the car parked with its engine running and hazard lights flashing.
Police evacuated Times Square. In the car's boot they found all the ingredients for a homemade bomb including propane gas cylinders, fireworks and two clocks, a metal gun locker containing fertiliser.
From the car's vehicle identification number, police traced the woman in Connecticut who sold the car to Faisal Shahzad (pictured). She also gave police a mobile phone number and helped identify him from photographs.
Faisal Shahzad lived in this Bridgeport building. Mobile phone records showed he made several calls to Pakistan and to a fireworks store in Pennsylvania. Court documents said he had received bomb-making training in Pakistan.
Police arrested Mr Shahzad at 2345 EDT on Monday 3 May after he boarded a flight en route to Islamabad, Pakistan. Although his name was on a no-fly list, he had been allowed onto the plane.
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