"We may disagree with this, but I can tell you their existential threat is not Afghanistan, their existential threats aren't terrorists in their country. Their existential threat is India," Mullen told reporters during a luncheon with the Pentagon Press Association.
"And that's where they focus on. I do not think, they are going to not focus on that (existential threat from India). So they keep that. They keep training people. They keep rotating people to that as well," Mullen said when asked why Pakistan is not doing enough in the war against terrorism.
"So I would certainly put it in the category of they haven't done what we want them to do along the lines.
Although their frontiers corps two years ago were a force that wasn't well led, wasn't well equipped, wasn't well trained and now all those things have changed and they are much more capable fighting force than they were historically.
They have taken on eight or nine different campaigns on that western border," he said.
Noting that the Haqqani network and Quetta shura are the main efforts for Afghanistan, he said their priority has been to work on the threat internal to the country.
"We certainly worked hard to convince that they need to do more there and I do think they need to do more, with respect to both North Waziristan and Quetta. We worked hard to push them as hard as we can," he said.
"Certainly there are some who believe that the US should ratchet it back on material support, we should ratchet it back on financial support.
Certainly that is being discussed in the Congress and I would certainly see that as a possibility in the future," he said.
"But we are, I believe, suffering now in this relationship, because of a choice we made in 1990, to cut them off. I think that would be a disaster now and I think that would be a disaster in the future," Mullen said.
"All of us, including the President have reiterated, reaffirmed the importance of this relationship, and the need to have it sustained. All of us also recognize that it is under extraordinary pressure. It's been through tremendous amount, certainly in the last few months," he said.
"We have seen, we have the tendency to focus on the Bin laden piece, I understand that in February-March we went through the Raymond David issue which was an issue that tested us as well.
So we have been through a very-very rough time, so we are committed to sustaining that relationship because it is vital to the region and actually globally. But we recognize it is under great stress right now. We need to see our way through it," Mullen observed.