NEW YORK - A top US diplomat has called for stepped up cooperation between Pakistan, Afghanistan and the NATO coalition to stem cross-border attacks by militants into the Afghan side and emphasized that similarly the Afghan territory should not be used against Pakistan. "...We have to recognize that the central gravity of al Qaeda activity is now in that area, of Afghanistan-Pakistan region. The two have become intertwined ...", the US Ambassador to the United Nations, Zalmay Khalilzad, said on CNN. "And in order to deal with the Taliban part of it, besides going after al Qaeda militarily, is to get the situation in which the Taliban cannot use sanctuaries across the border from which they can launch attacks. "And similarly, of course, Afghan territory should not be used against Pakistan. So, there is a need for cooperation between the coalition, Afghans and Pakistan. That's vital for winning," the Afghan-born diplomat added. In an interview on CNN programme Fareed Zakaria GPS, Khalilzad also stressed the need for India-Pakistan cooperation against extremism in the wake of Mumbai attacks, and cautioned against the impact of any confrontation between the two nuclear neighbours on the fight against terrorism. He said that "the attack in Mumbai has the risk, if it is not managed well, to divert the attention of Pakistan from the west, on Taliban and al Qaeda, to the east." "And so, therefore, it's very important strategically... that those who are responsible are prosecuted for the Mumbai attack, that the two countries cooperate also against this common enemy of extremism and terror," he added. Khalilzad praised the recent Pakistani actions against terrorists on its side of the Afghan border and said President Asif Ali Zardari has a firm commitment to anti-terror cooperation with Afghanistan. "I think the recent (Pakistani) efforts have been very encouraging. I think the relationship also at the political level is very encouraging between presidents (Hamid) Karzai and Zardari. I know that President Zardari is very much committed to cooperation on this effort, and we need to build on that."