Contending that US relationship with Pakistan had reached a dead end, an American lawmaker has said there was a sense among Congressmen that time had come to 'side' with India to 'cut off the ISI'.

Senator Mark Kirk said at a discussion forum by prestigious Washington-based think tank, Foreign Policy Initiative, that a US-India tie-up was ISI's 'horror story' but time had come for it to evolve.

"You know, Yogi Bear said when you reach a fork in the road, take it. I think we hit the fork in the road in August and September between the United States and Pakistan. We saw a large truck bomb assembled, lit off next to a US base, 77 US casualties," Kirk said.

In recent times US' ties with Pakistan, a key ally in the region, have plunged to an all-time low following a series of incidents over the year, including the killing of two people by a CIA contractor, the Abbottabad raid, and finally the NATO airstrike that killed 24 Pakistani soldiers.

"My sense of the Senate and probably the House is we're ready to take that fork in the road. We're ready to side with India, to cut off the ISI," the Illinois Senator said.

"It appears to me the Pakistani horror story of us siding with India should now evolve. Pakistan has decided we're leaving. Pakistan has decided that they can cripple the civilian government," he said.

The United States, he said, needs a stable party in the region who has a status quo pro-civilian anti-terror interest, which is India.

"And in many ways, this is the ISI horror story, but I would say they picked this, and we should now arrange that fate for them," he said in response to a question. Kirk urged General Martin Dempsey, chairman of the Joint Chiefs of Staff, to play what he called 'hard ball' with Pakistan.

"Get in with the Indian Intelligence Service, the Indian Chief of Staff, bring Indian, not just economic but military assistance on line, and build some long relationships so that in the mid-presidential term next time, the 2014 time frame, you have a steady partner with new money coming on the table that can send an important signal to Afghanistan," Kirk said.

Appearing on the same discussion forum, Congressman Adam Kinzinger, noted that in many cases, actors react more favourably when you are willing to use the stick as a way to get your will done.

"I think as a nation, we have to begin exploring more of those options. How to be a little more difficult, how to be a little harder, how to hold the Pakistanis a little more accountable," he said.

Kirk said he saw the war on terror in the Af-Pak region as a Vietnamese scenario for the US, which should not allow this to happen.

"At the same time, I see this as kind of a North Vietnam scenario, we are fighting in South Vietnam while the North Vietnamese are fighting against us, and we simply allow it to happen," the Congressman said.

"At the same time, there should be no doubt that going into the stick approach talking about reducing aid, talking about allying with some of their strong enemies, is going to create a big heartburn in the area. It is going to make it worse. It is going to make it difficult," he said.