By Arun Kumar 

Washington, May 7 (IANS) The death of Al Qaeda leader Osama bin Laden could be a "game changer" for US military efforts in Afghanistan, according to US Defence Secretary Robert Gates.

"Well, I think in terms of the impact of the killing of Osama bin Laden, in terms of the situation in Afghanistan, I think that there is a possibility that it could be a game changer," Gates told troops at an Air Force Base in North Carolina Friday.

"Bin Laden and (Taliban leader) Mullah Omar had a very close personal relationship and there are others in the Taliban who have felt betrayed by Al Qaeda, that it was because of Al Qaeda's attack on the US that the Taliban got thrown out of Afghanistan," he said.

"Frankly I think it's too early to make a judgment in terms of the impact inside Afghanistan but I think in six months or so we'll probably know if it's made a difference," Gates said.

US relations with Pakistan were complex, Gates said. He said he would have been astounded if someone had told him two years ago that Pakistan would have 140,000 troops on its western border with Afghanistan.

"I would have said that's not going to happen, but it has," Gates said noting, Pakistan has pulled troops from its border with India and has taken thousands of casualties in the fight against the terrorists.

The United States and Pakistan are firm partners in the fight against terrorism, Gates said. "At the same time there is no question that they hedge their bets," he said of Pakistan's leadership.

But Pakistan and the United States have to keep working on their relationship, Gates said. At the tactical level-across the border with Afghanistan-the relationship is good and getting better, he said.

US and Pakistani forces take turns being the "hammer and anvil" with the Taliban stuck in the middle.

"I would say it is a relationship we just have to keep working at," Gates said.