Finding Osama bin Laden is "like looking for a needle in a haystack" but he will be found, US Defence Secretary Mr Donald Rumsfeld said this evening.
He has told a news conference at the White House that he was confident bin Laden would be caught eventually.
His statement is an apparent about-face from an interview with USA Todaynewspaper in which he said he feared US forces may not be able to catch or kill bin Laden.
However, Mr Rumsfeld said today he had been mis-represented by the newspaper's headline.
He is reported as telling the newspaper that even if bin Laden were captured, the al-Qaeda terrorist network would be able to carry on without him.
"I just don't know whether we'll be successful," he was reported as saying. "Even if he were gone tomorrow, the same problem would exist".
He said bin Laden's wealth may make it difficult to locate him. "It's a big world," he said. "There are lots of countries. He's got a lot of money, he's got a lot of people who support him".
But Mr Rumsfeld pledged the US will succeed in bringing down the Taliban government in Afghanistan.