"There are certainly indications that's the case," The Dawn quoted Admiral Mullen, as saying.
Talking to media persons right after President Barack Obama announced a revamped strategy for Afghanistan and Pakistan, he said that the nefarious network must be severed to thwart the extremist's upsurge in the region.
Fundamentally that's one of the things that have to change," Mullen added.
He said Islamabad has also expressed concern over the increasing influence of the outlawed terror groups and was working to curb the menace, but more sincere efforts were needed to tackle the issue.
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.
Admiral Mullen highlighted the fact that although the US is offering Pakistan all help, there still exits a 'trust deficit' between both the countries.
Talking about the new policy for the region, he said the Obama Administration has taken a 'more regional' approach to the issue so that the Pakistani forces do not always remain occupied with the Kashmir issue.
"One of the reasons the regional approach is so important is to de-tension the Kashmir border so that the Pakistani military is not completely tied up on that border, and they are able to train, equip and fight on the western border in the counter-insurgency effort," Mullen said.
Head of US Central Command, General David Petraeus also echoed Mullen's stance.
General Petraeus claimed that the Pakistani intelligence had established some of the militant groups with the help of US funding with an aim to flush out Soviet forces from Afghanistan.
"Those links were very strong and some of them, I think, unquestionably do remain, to this day. It is much more difficult to tell at what level those links are still established," he said. (ANI)