As U.S. forces swept central Iraq in search of armed opponents, Defense Secretary Donald H. Rumsfeld said yesterday the military is fighting a war against five disparate groups with their own agendas and not a guerrilla conflict waged by an organized insurgency.

Speaking to reporters at the Pentagon, Rumsfeld dismissed suggestions that 146,000 U.S. troops in Iraq are engaged in a guerrilla war or bogged down in a Vietnam-like "quagmire."

Rumsfeld said the five groups opposing U.S. forces -- which he identified as looters, criminals, remnants of Saddam Hussein's government, foreign terrorists and Iranian-backed Shiites -- "are all slightly different in why they are there and what they are doing."

"That doesn't make it anything like a guerrilla war or an organized resistance," Rumsfeld said. "It makes it like five different things going on [in which the groups] are functioning more like terrorists."

One reporter quoted the Pentagon's own definition of guerrilla war -- "military and paramilitary operations conducted in enemy-held or hostile territory by irregular ground indigenous forces" -- and told Rumsfeld, "Seems to fit a lot of what's going on in Iraq."

To which Rumsfeld replied: "It really doesn't."

Rumsfeld called Iraq the latest battlefield in the global war on terrorism aimed at getting al Qaeda terrorists out of Afghanistan and Hussein out of Iraq, to "allow the people of those countries to take over their countries."

"How long or how successful the remnants of the Saddam Hussein regime will be in attacking coalition forces and attacking Iraqi infrastructure, I don't know," Rumsfeld said. "We're going to try to find them. We're working very hard at it."

Rumsfeld said he is supporting efforts by L. Paul Bremer, the U.S. civilian administrator in Baghdad, to push "as fast and as hard as he can to get Iraqis engaged in aspects of [the reconstruction] process. The sooner that happens, in my view, the greater the likelihood that the people of Iraq will feel a stake in what's taking place."

W. Patrick Lang, former head of Middle Eastern Affairs at the Defense Intelligence Agency, said the situation in Iraq is "exactly" what a guerrilla war looks like in its early stages.

"It's not unusual for there to be more than one guerrilla group in an insurgency," Lang said in an interview. "It doesn't mean that they won't be able to sufficiently overcome their differences to have an effect against us."

Twenty-three U.S. troops have been killed since President Bush declared an end to major combat operations on May 1. The Iraqi insurgents could ultimately force U.S. troops to stay in heavily guarded bases, surrendering "a lot of ground to effective control of the other side," Lang said.

Retired Army Gen. Barry R. McCaffrey, who commanded the 24th Infantry Division during the 1991 Persian Gulf War, called the Iraqi opposition to U.S. forces "an organizing guerrilla war in which right now we still lack a useful tactical intelligence system. We can't begin to deal with this problem until we put huge resources into building Iraqi police forces and infantry battalions."

In other Iraq-related developments, Rumsfeld and Gen. Richard B. Myers, chairman of the Joint Chiefs of Staff, defended the intelligence that prompted U.S. forces to attack an Iraqi convoy in western Iraq near the Syrian border on June 19 in the belief that high-ranking former Iraqi leaders were attempting to flee the country.

"It was good intelligence about potential high-value targets, but we didn't know who," Myers said. "We just knew there was an attempt to flee Iraq, and so we went after the targets."

Rumsfeld said that it was "entirely possible people got away" from the convoy and managed to escape on foot across the Syrian border. He added he still does not have "perfect visibility" about whether five Syrian border guards, wounded by U.S. forces and returned to Syria on Sunday, played any role in helping the fleeing Iraqis.

Defense Secretary Donald H. Rumsfeld said Iraqi opposition comprises five different groups, and "that doesn't make it anything like a guerrilla war."