Washington ? Jordanian terrorist Abu Musab al-Zarqawi probably has escaped from Fallujah, but U.S. and Iraqi troops have up to 3,000 insurgents trapped in the city and should defeat them within several days, the American commander said Tuesday.

“I think we’re looking at several more days of tough urban fighting,” said Lt. Gen. Thomas Metz, commander of ground forces in Iraq and of the U.S. Army’s III Corps, based at Fort Hood. “The fight in Fallujah is far from over.”

Speaking of al-Zarqawi, who is accused of beheading American and other hostages in grisly videotapes posted on the Internet, Metz said it was “fair to assume that he has left.”

The self-proclaimed ally of Osama bin Laden was said to be operating in recent months from Fallujah, a Sunni Muslim insurgent hotbed that U.S. warplanes bombed repeatedly in attempts to kill him.

Other top leaders of the insurgency “probably” have left the city as well, Metz said, noting that “it wasn’t until night before last that we really began to seal off the city completely.”

Since Sunday, he said, the force of about 15,000 U.S. and Iraqi troops in “Operation Dawn” had encircled the insurgents remaining and was pushing them into the center of the city.

Metz said the number of insurgents encountered so far was “about what we expected.” U.S. commanders estimated before the battle began that 2,000 to 3,000 guerrillas and foreign Islamist terrorists were in the city, regarded as the headquarters of the insurgency.

Defense analysts in Washington said such estimates could be wildly off the mark. They also questioned Metz’s suggestion that coalition forces would be able to prevent the insurgents from escaping from Fallujah or melting into the population to fight another day.

“This is a city that’s relatively small and easy to seal off,” said Anthony Cordesman, an expert at the conservative Center for Strategic and International Studies who follows events in Iraq closely. “But you can exfiltrate out of almost any loose net — especially when people are in combat. You can simply put down your arms and blend in.”

“The problem we have here is that no one knows what any of these numbers mean,” he added. “You simply have no way to know whether Zarqawi was in Fallujah recently. We don’t know how well organized the insurgents are. We don’t know how many are outside Fallujah.”