Over the past 10 days, US forces have surged into the Baathist stronghold of Fallujah, raided suspected terrorist camps in northern and western Iraq, and battled armed irregulars in the Balad area northeast of Baghdad.

The full scope of the operations are still secret, but they were clearly the biggest since President George W. Bush declared on May 1 the end of major combat operations in Iraq, and suggested that the war is far from over.

US commanders said the 147,000 US troops now in the country are sufficient to stabilize Iraq but they did not know when conditions will allow soldiers to begin going home.

"We do have plans, but they're all conditions-based. It depends on what the enemy does," Lieutenant General David McKiernan, the commander of coalition ground forces in Iraq, told reporters Friday.

As US troops have increased their presence throughout the country in order to restore order and security, they have been targeted by hit-and-run attacks, mainly in the predominantly Sunni areas north of Baghdad.

By the Pentagon's count, 40 US military personnel have been killed since May 1 -- a dozen of them by hostile fire, and most of those in the past three weeks.

US Defense Secretary Donald Rumsfeld acknowledged this week that it may take months to root out resistance, and the failure to capture or otherwise account for deposed Iraqi President Saddam Hussein was making the task of pacifying the country more difficult.

But McKiernan and other US commanders believe that the resistance is locally organized by remnants of the former regime -- and not a nationally orchestrated campaign of resistance.

The core of the resistance is believed to be from Fedayeen Saddam, Baathist militants, Iraqi Intelligence Service and Special Republican Guards who survived the war intact in an "iron triangle" running from Baghdad north to Fallujah and Tikrit.

They went to ground rather than fight after watching their comrades mowed down in the south by US forces.

Their strategy now appears to be to bleed US forces with small scale attacks, driving up the political costs of an occupation.

Some military analysts here believe they are vulnerable, however.

"It almost has about it a sort of Darwinian aspect," said retired Major General Robert Scales, former head of the US Army War College.

"That is very, very common in warfares in history where the main phalanx of the enemy has been broken and what you're left with are fragments that have been unaddressed, that need to be taken out," he told AFP.

"It needs to be done expeditiously because the last thing you want is a groundswell develop of a popular form of resistance, which is not likely to happen with this regime," he said.

"But the sooner that you take down the remnants of the Baathist regime, the less opportunity you're going to have to give any type of support or sense of purpose to anybody who happens to remain," he said.

He said he did not believe the Baathists were regrouping. If they were, he said, one would likely see attempts to mount coordinated nationwide uprisings to tax the capacity of US forces to respond.

"You can see from the casualty numbers this is not the Tet offensive by any stretch of the imagination," he said.

Instead, with their forces gathered in one area, the Baathists risk destruction "in detail" by the concentrated application of US force, according to Scales.

US commanders, however, are not predicting a quick end to the resistance. By some accounts, US officials now believe US forces will be needed for two years or more.

"This is not a black and white deal," Scales acknowledged. "The gray area of transition from war to no war, particularly in modern war, is always done in fits and starts, and it always appears to be more chaotic than it really is.

"But, gosh, who knows how long this could take. It could take a long time. But every time the military goes in and does what they're doing the overall level of violence seems to decline to a certain degree," he said.

WAR.WIRE