(CBS) Defense Secretary Donald Rumsfeld said in an interview published Tuesday that Osama bin Laden's militant al Qaeda network remains active around the globe but there is no sign the Saudi-born dissident is formally directing its activities.

“My guess is, if he were active, we would know it - we would have some visible sense of it, which we haven't seem to have had, for some reason,” he told The Washington Post in a story for Tuesday editions. He added he did not know whether bin Laden was simply lying low or was ill or dead.

Rumsfeld will leave Tuesday on an extended trip to Europe and the Persian Gulf to discuss the war on terrorism and other issues. He also plans to visit India and Pakistan but the timing has not been set, the official said.

The dangers posed by Iraq's nuclear ambitions will be a topic of discussion when Rumsfeld visits allied nations in the Gulf, but he will not be seeking support for a U.S. invasion, a defense official said Monday.

“We're not at the stage where we're going around soliciting allies for something like that,” said the official, who discussed aspects of Rumsfeld's trip on condition that he not be identified.

Rumsfeld told the Post he did not know whether bin Laden was laying low for security reasons, suffering from an illness, or dead. However, the Pentagon chief said the U.S. government has evidence that other al Qaeda leaders are still raising money and communicating with one another.

“We know they're in enough countries and have enough money and have enough leadership that you've got to expect they, in fact, are going to be back again,” Rumsfeld said. “There have to be six, eight, 10, 12, 15 people who know where the bank accounts are, who know people who were trained, who know what their techniques are, who can pick it up.”

Washington launched a military assault on extremists in Afghanistan eight months ago to crush al Qaeda, which it blames for the Sept. 11 attacks on the United States. While the U.S.-led campaign quickly toppled the government of al Qaeda's Taliban protectors, bin Laden escaped capture and has maintained a low profile.

The Post said Rumsfeld again acknowledged that large numbers of al Qaeda fighters escaped, fleeing into Pakistan.

“There are pockets of al Qaeda and Taliban still floating around on both sides,” Rumsfeld said in the interview, adding that finding them in the remote, mountainous region was like searching for “a needle in a haystack.”

He also told the Post that Pakistan had not made a large-scale reduction in the number of its forces deployed to help in the hunt for al Qaeda and Taliban remnants, despite rising tension with India over the disputed Kashmir region,

“The Pakistanis have moved away some small elements but not major forces yet - some reconnaissance people and some communications people, nothing big,” Rumsfeld told the Post. “The forces are still reasonably in place along the Afghan border.”

On Iraq, Rumsfeld was quoted as saying that President Saddam Hussein's government was more of a threat now than it was in December 1998, when U.N. weapons inspectors left Iraq in advance of U.S. and British airstrikes.

“There's no question but that their weapons of mass destruction program and their military capabilities are going to evolve in ways that are favorable to them,” Rumsfeld said.

However Rumsfeld made it clear that an invasion of Iraq would be a major undertaking for the U.S. military. He strongly disagreed with some military strategists who have said toppling Iraqi President Saddam Hussein would be a “cakewalk,” the Post said.

“Listen, nothing is a cakewalk,” Rumsfeld said. “Everything is unpredictable, and life is hard. Those folks have weapons that they'll use, and anyone who thinks it's a cakewalk isn't right.”