"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," Admiral Mullen told the popular National Public Radio (NPR).
"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.
Last week at a Congressional hearing, Mullen triggered a storm in Pakistan by his statement that Haqqani network was a "veritable arm" of the ISI, which evoked sharp reaction from Islamabad.
Mullen said he would not change a word of his testimony.
"I phrased it the way I wanted it to be phrased," he said in the interview.
Mullen, who has met General Ashfaq Pervez Kayani, the Pak Army Chief at least 30 times in the last two and half years, said he spoke to the latter about taking action against the Haqqani network.
"I've talked about them supporting it. When Gen. Kayani and I have talked about this in the past, he's not a big fan of the Haqqani network."
It's a very lethal, very virulent insurgent terrorist group that you just can't walk up to and eliminate. So it isn't anything that could be done anywhere close to overnight. We talked about how to do it in the past, from my perspective, that's really up to the Pakistanis to figure out," he said.
However, White House Press Secretary Jay Carney refrained from using the term that the "Haqqani network is a veritable arm of the ISI" even though pressed repeatedly by the White House press corps at his daily news conference.
"As I've said and others have said, is that the continuing safe havens that the Haqqani Network enjoys in Pakistan and the links between the Pakistani military and the Haqqani Network are troubling, and we want action taken against them. That is a conversation we have had with the Pakistani government for a long time, not just in recent days and weeks," Carney told reporters.