"What we need to do is try and help the Pakistanis understand these groups are now an existential threat to them," US Defence Secretary Robert Gates said.
Gates said there is appropriate evidence that the ISI has maintained links with terror groups for long now.
He said Washington has been tendering all help to Islamabad to root out extremism from the region, and would continue its support in future also.
"We will be there as a steadfast ally for Pakistan. They can count on us," The Daily Times quoted Gates, as saying.
Earlier, US Joint Chiefs of Staff chairman, Admiral Mike Mullen had also confirmed media reports that ISI has close links with al Qaeda and the Taliban network, and is offering logistical support them.
"There are certainly indications that's the case," Admiral Mullen had said.
On the other hand, Pakistan, in recent times, has rebuked US allegations that the ISI is backing the Taliban and al Qaeda against the US led allied forces in Afghanistan.