Washington/New York, May 7 (IANS) US investigators probing the aborted Times Square bombing attempt have shifted their focus to prime suspect Faisal Shahzad’s links in Pakistan and a counter-terrorism expert has said two or more groups could have worked together in grooming Shahzad for a terrorist mission.

Meanwhile, the US is planning to send Pakistan a detailed request for ‘urgent and specific assistance’ in the aborted bombing case, the Washington Post reported.

According to the daily, a US counter-terrorism official was cited as saying it was possible that two or more groups had worked together in grooming Shahzad for a terrorist mission during an extended trip he made to Pakistan last year.

The influential daily cited US officials as saying that they had reached no firm conclusion about whether Shahzad had ties to any domestic militant group in Pakistan, but that information gathered thus far continued to point to the Pakistani Taliban, which has asserted responsibility for the bombing attempt.

The question of which group, if any, was involved is an important one for the future of the uneasy counter-terrorism alliance between the United States and Pakistan, it said.

‘The Pakistani military has been waging war against the Pakistani Taliban for more than a year, with US assistance,’ the Post said.

‘But Pakistan might be more reluctant to take action against other groups, particularly those focused on separating the disputed region of Kashmir from India.’

‘Some, particularly the Lashkar-e-Taiba, thought responsible for terrorist attacks in India, have strong support within the Pakistani intelligence service,’ it noted.

The Post cited Pakistani officials aiding in the Times Square case as saying they have arrested some people linked to a third group, Jaish-e-Muhammad, which is focused on Kashmir but has also turned its efforts against US troops in Afghanistan.

US intelligence suspects there is increasing overlap and coordination among domestic Pakistani groups and the Pakistan-based Afghan Taliban and Al Qaeda, the daily said.

The Post said pressure on Pakistan to escalate its domestic counter-terrorism operations, particularly toward Kashmir – and India-focused militants, could increase anti-US sentiment there, while any perceived Pakistani hesitation would undermine congressional and public support in the US.

White House spokesperson Robert Gibbs told reporters that the justice department and investigating agencies are actively looking at the time which Shahzad spent in Pakistan, but did not go into details.

The New York Times also cited unnamed officials as saying that after two days of intense questioning Shahzad, an American citizen of Pakistani origin, evidence was mounting that the Pakistani Taliban had helped inspire and train Shahzad in the months before he drove the car bomb to Times Square Saturday night.

Officials said Shahzad had discussed his contacts with the group, and investigators had accumulated other evidence that they would not disclose.

On Wednesday, Shahzad, the 30-year-old son of a retired senior Pakistani Air Force officer, waived his right to a speedy arraignment, a possible sign of his continuing cooperation with investigators, the Times said.

One senior Obama administration official cited by the Times cautioned that ‘there are no smoking guns yet’ that the Pakistani Taliban had directed the Times Square bombing.

But others said that there were strong indications that Shahzad knew some members of the group and that they probably had a role in training him. American officials said it had become increasingly difficult to separate the operations of the militant groups in Pakistan’s tribal areas.

Besides the Pakistani Taliban and Al Qaeda, groups operating in the tribal areas are the Haqqani Network and the Kashmiri groups Lashkar-e-Taiba, blamed for the Mumbai terror attacks, and Jaish-e-Muhammad.

Meanwhile, the Wall Street Journal said Shahzad possibly received instruction from the Pakistan Taliban’s suicide-bomb trainer.

If verified, the suspected links between Pakistan Taliban and Shahzad would mark a stark shift in how it and related jihadist groups, which have so far focused on attacks within Pakistan and in India, not the US, pursue their goals, it said.

Pakistani investigators are also probing Shahzad’s possible connections with Jaish-e-Muhammad, an outlawed Islamist militant group, after the arrest Tuesday of Tohaid Ahmed and Mohammed Rehan in Karachi, the Journal said.

The two men were believed to have links to Jaish, it said citing a senior Pakistani government official. Ahmed had been in email contact with Shahzad.

Rehan took Shahzad to South Waziristan, the official was quoted as saying. There, Shahzad received training in explosives in a camp run by Qari Hussain, a senior commander with Tehrik-e-Taliban Pakistan who trains suicide bombers, the official was quoted as saying.

Hussain is also a cousin of Hakimullah Mehsud, the Pakistan Taliban’s chief.

Hussain claimed responsibility for the attempted attack in a weekend audio message. His message followed a video of Mehsud, the Pakistan Taliban leader, in which he warned of a wave of attacks on the US. ‘Our fighters are already in the United States,’ said Mehsud.