U.S. Defense Secretary Robert Gates said Friday that the killing of Osama bin Laden could affect the situation in Afghanistan.

The death of the al-Qaida leader "could be a game changer" in Afghanistan, but it will take time before the situation clarifies, Gates said during his visit to Seymour Johnson air force base in North Carolina.

"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-Qaida -- (they feel) it was because of al- Qaida's attack on the United States that the Taliban got thrown out of Afghanistan," the American Forces Press Service quoted the secretary as saying.

It may become clear in six months or so how bin Laden's death has affected al-Qaida operations in Afghanistan and elsewhere, Gates said.

The killing of the terrorist mastermind, which was confirmed by al-Qaida Friday, occurred at a crucial time when Pentagon officials and military commanders are still working on the specifics of the planned troop withdrawal from Afghanistan.

White House press secretary Jay Carney said earlier this week that the plan is on track to begin withdrawing troops from Afghanistan in July, while the pace of the drawdown depends on conditions on the ground in Afghanistan.