KABUL, Feb 26: Osama bin Laden will probably be captured or killed one day, US Defence Secretary Donald Rumsfeld said on Thursday, but he added he had no idea when.

Mr Rumsfeld was speaking at a news briefing with Afghan President Hamid Karzai outside the presidential palace here.

Asked if US and allied forces were getting closer to capturing the world's most wanted man, the US defence secretary said: "Close doesn't count. The world will be a better place when he is captured or killed.

That is the goal of a great many nations... I suspect that we'll find that it is accomplished at some point in the future and I wouldn't have any idea when."

The US military in Afghanistan has made confident predictions that Osama bin Laden would be caught soon. Mr Rumsfeld also praised recent efforts by Pakistan's army along the Afghan-Pakistan border to hunt militants there.

"I think the efforts that are being made in Pakistan...to track down terrorists are encouraging and constructive and in a number of instances they have been successful."

His visit, winding up a week-long tour of Iraq and Central Asia, came just hours after five Afghan aid workers were killed and three wounded in an ambush northeast of Kabul, the worst such attack since US-led forces overthrew the Taliban in 2001.

Hamid Karzai said people should not blame every attack on militants, when often banditry was to blame. "Every act that is committed by a Kalashnikov is not an act done either by the Taliban or Al Qaeda," Mr Karzai said. "We strongly believe (in) evidence that they are defeated. They are gone."

Security was heavy for Mr Rumsfeld's visit. When his C-130 aircraft flew into Kandahar and Kabul it made a steep "tactical" descent to avoid any possible threat from shoulder-fired missiles. -Reuters