Standing by his statement that Haqqani network is the "veritable arm" of the ISI, Mullen asserted that Pakistan Army uses terror groups like Haqqani network and LeT to serve its security interests.
The depiction of Kayani as the most powerful man in Pakistan was made by Mullen, who was long considered to be the closest friend of Pakistani generals in an interview to the popular National Public Radio (NPR).
Mullen, who hangs his fighting boots at the end of this month said that Kayani wants a secure border on both sides of Pakistan, to a question if the general was seeking peace with India.
"In many discussions I've had with him, he would much rather have a stable, peaceful environment on both his borders than the one he has right now," Mullen said in response.
"Does Gen. Kayani want to make peace with India- a durable peace with India?" the Admiral was asked by the Radio.
"You asked me about what he feels, what he believes and what we talk about. I think that's the longer-term view, is peace and stability on those two borders, which is what would present opportunities to have a growing economy, forward investment a stable country moving in the right direction," Mullen said. In the last two and half years, Mullen has met Kayani about 30 times.
"The military is a very important organisation in that country, but it shouldn't be the only organisation that we engage," Mullen said.
"Engagements with the civilian leaders, engagements with the economic leaders, engagements in the region," he said.
I've said for a long time: I think unlocking Kashmir, which is a very difficult issue on the Pak-Indian border, is one that opens it all up, and I think - I believe we have to continue to try to, all of us, figure out a way to work that as well," Mullen observed.
Recalling his visit to Pakistan in 2008, the American military chief said, "One of the things that I spoke to the political and military leadership about was this whole issue of supporting insurgent groups or proxies.
And another one that, quite frankly, historically, has been support has been LeT, basically, originally created to focus on the challenges in Kashmir." "They are now actually spreading west. But it's part of the strategy, from my perspective, that is there to enhance the security of the country. That's how it is thought about there," Mullen said.
"You're saying the Pakistanis think of these groups as weapons that they can use at some point," he was asked.
"Clearly to ensure that their security is going to be improved," Mullen said.
"The ISI specifically has enough support for the Haqqanis in terms of financial support, logistic support -and actually, sort of free passage in the safe haven- and those links are part of what enable the Haqqanis to carry out their mission," Mullen said.
"I just think those links have to be broken. I don't believe they can be broken overnight, but if they're broken, I think that fundamentally changes the viability of that safe haven and the overall strategy," he asserted.
Mullen said he would not change a word of his testimony.