Calling the Taliban-linked Haqqani network a 'common enemy', the US has made it clear to Pakistan that both countries have to work together to deal with the dreaded terror outfit responsible for attacks on coalition forces based in Afghanistan.

Stating this, Defence Secretary Leon Panetta said Pakistan too has been a victim of terrorism and cited the recent killing of 17 Pakistani soldiers by the Tehrik-e-Taliban Pakistan (TTP).

"They lost 17 Pakistanis on a patrol to the TTP. And so every day they too are the victims of terrorism," he noted.

"So we have a common enemy. It would make sense if we could work together to confront that common enemy," Panetta told reporters at Pentagon on Friday responding to a question on the Haqqani network.

It is in the interest of Islamabad as well to take action against the Haqqani network, he said. "I think he (General John Allen, Commander of US and NATO forces in Afghanistan) got a receptivity from (Pakistan army chief) General (Ashfaq Pervez) Kayani that he understood the concern," he said.

On closure of the NATO supply routes by Pakistan, Panetta said the US continues to have discussions with Islamabad on reopening of the ground lines of communication (GLOCs).

"There continue to be discussions in this area. We continue to have a line of communications with the Pakistanis to try to see if we can take steps to reopen the GLOCs. And you know, the good news is that there continue to be those discussions," Panetta said.

"There still are some tough issues to try to resolve. But, you know, I think the important thing right now is that both sides, in good faith, keep working to see if we can resolve this," he said.

Meanwhile, an eminent US expert told lawmakers at a Congressional hearing that given Pakistan's reluctance to take action against the Haqqani network, the US should continue with its drone strikes.

"I believe we need to launch drone and/or special operation strikes on Haqqani and Afghan Taliban leadership targets within Pakistan. They cannot have impunity to operate within Afghanistan as they currently have if we expect to be at all successful in the long run in Afghanistan," said Max Boot, senior fellow for National Security Studies at Council on Foreign Relations.

Appearing before the same Congressional committee, (Retd) Army General Jack Keane, former army vice-chief of staff, argued that the US should take the Pakistani supply route off the table.

"Obviously we've had our main supply route closed for a number of months now and we're able to sustain the force that we have. Two means to do that is the other supply route in the north and also the air line of communication that we've established," he said.

"I think it's overstated, our dependency on that main supply route. It certainly is desirable because it's a lot easier to use. It's less costly, although the Pakistanis certainly want us to pay through the nose for the challenges that we had between them.''

"So I think we could actually take the issue off the table in my judgment in terms of our relationship with Pakistan on this issue because we do have alternatives. And most dramatically, our force size is coming down rather significantly, and therefore there's less requirement," Keane said.

Pakistan had closed the supply routes after a NATO raid killed 24 of its soldiers in November last year.

Michael O'Hanlon, director of research, senior fellow and chair at Brookings Institution's Foreign Policy Programme said at the hearing that logistically the US now is in a much better place vis-a-vis Pakistan.

"My hat's off to our military logisticians and our diplomats who have developed the northern distribution network. It's an amazing alternative," he said.

"It still increases slightly uncomfortably our dependence on (Russian President) Vladimir Putin, but some of those routes don't require his explicit permission, and in any event we're in a much better place," he told lawmakers.

Boot said the US has tried very heavily subsidising the Pakistani army over the course of the last decade in an effort basically to wean them away from the Taliban, the Haqqanis, to basically 'bribe' them, in a way, into becoming US allies. "That effort has totally failed," he argued.

"As a starting point, we need to recognise that effort has failed, that the Pakistanis remain as deeply committed to the Afghan Taliban, the Haqqani network, now as they were a decade ago.

"And so, for that reason, I think it's been counter-productive to give all the subsidies that we've given to the Pakistani military, which in essence has been basically indirectly subsidising the very forces that are killing our personnel in Afghanistan," he said.

"I'm not saying cut off all aid to the state in Pakistan. I think we should certainly continue to fund civil society in Pakistan in an alternative to the military-dominated, ISI-dominated foreign and national security policy they pursue. But I think we need to recognise that Pakistan is not our friend here and that giving further subsidies to the military will be counter-productive," Boot said.

He said: "I don't think it would lead to the kind of consequences that some people fear, such as 'jihadist' takeover of the state, because I believe that the Pakistani military is still very good at internal control and will still be able to remain in power."

"But their resources that they use, in large part, for subsidising, for preparing for war against India and for subsidising 'jihadist' groups that attack ourselves and our allies, those resources will be decreased," Boot said.