NEW YORK - The top American soldier has rejected media reports about Pakistan having been put on notice that the United States would strike if a terror attack on the US soil could be traced back to the South Asian country, saying Washington was more concerned with Islamabads cooperation in the fight against extremists. Appearing on 'Fox News Sunday, the Chairman of the Joint Chiefs of Staff, Admiral Mike Mullen, said the US was not weighing military action against Pakistan in retaliation for a terror attack in the US emanating from there. Reports this week of contingency planning for a possible military strike followed news that the alleged attacker in the failed Times Square car bombing last month had ties to Pakistan. Mullen said he was pleased with the increase in Pakistani military assistance in the region as NATO forces fight Taliban and al-Qaeda terrorists who flooded into Afghanistan from the porous Pakistani border. I mean, were very concerned about that part of the world. Were very concerned about - thats where al-Qaeda leadership lives. We know that. And were working with Pakistan and, quite frankly, with Afghanistan to continue to put pressure on that leadership. And I wouldnt speak to any kind of details in terms of either plans or operations. The Chairman added that the Nato-led counterinsurgency effort in Taliban stronghold of Kandahar is critical to success in Afghanistan. The Kandahar campaign is scheduled to begin next month and has been compared in importance to the overall war effort as Baghdad was during the US surge in Iraq in 2007. I think Kandahar will give us very clear evidence of how this strategy is proceeding. It is the home of the Pashtun resistance. It is central to the insurgency. So I think success in Kandahar over the next many months is absolutely critical to the longer-term outcome in Afghanistan, Mullen said. The chairman said he hoped that United Nations efforts will help stabilize Iran and North Korea, both of which are facing sanctions - North Korea for sinking a South Korean submarine, killing 46 sailors, and Iran for violating international rules on developing highly enriched uranium. North Korea denies that it sank the submarine and has threatened retaliation for any punitive action. But Mullen said North Korean leader Kim Jong Il tends not to stop after a single provocative move, and could be planning something else. The goal remains to certainly not have a conflict break out. That said, North Koreans committed, you know, a heinous act, if you will, he said. And Im concerned theres with Kim Jong-Il ... you know, there could be follow-on activities. As for a nuclear Iran, Mullen said he hasnt given a lot of thought about how to contain that situation, calling it a hypothetical concern that is left for political leadership to ponder. Intelligence estimates suggest Iran could have nuclear weapons in the next couple years. Its a longer-term concern. And when we - if for some reason, we ever got to that position, then I think wed address that issue. I havent spent a great deal of time on that up to this point, he said. Mullen said that he was hopeful that preliminarily approved sanctions at the United Nations Security Council actually get put into effect. I think its very important in that regard because of the ability or the legitimacy in terms of moving forward and continuing to isolate Iran, as Iran continues to isolate itself. That said, the destabilizing impact of them achieving weapons capability, along with the destabilizing impact of striking them from whomever it came, is something I continue to be extremely concerned about, he said.