SAMARRA, Iraq — Eight months after the fall of Baghdad, U.S.-led forces in Iraq are facing a prolonged campaign against insurgents who have shown increasing sophistication in tactics, strategy and intelligence-gathering, according to military officials and analysts.
An insurgency that kicked off with frenzied pot shots and stray bombings by seemingly ragtag gunmen has coalesced into an effective, guerrilla-style war of attrition featuring a daily drumbeat of attacks interspersed with sensational strikes.
The insurgents have learned to mount targeted bombings, crippling sabotage, helicopter shoot-downs and -- in this volatile city north of Baghdad -- a synchronized urban ambush with scores of fighters firing machine guns, rocket-propelled grenades and mortar shells at U.S. formations.
"There was coordination -- to say otherwise would make no sense," said Col. Frederick Rudesheim, commander of the 3rd Combat Brigade here, which said its forces killed as many as 54 insurgents in the Nov. 30 firefight, a figure widely disputed by residents. "They put together an attack. And they didn't do it overnight."
In an effort to assess where the U.S.-led occupation stands at the end of the year, two reporters spent several weeks interviewing commanders, regular soldiers and pro- and anti-American Iraqis throughout the battle zone. Although U.S. officials remained confident of victory, they and almost everyone else agreed that an already bloody conflict is about to get worse.
No one anticipates anything but fiercer combat until at least next summer, when the U.S.-led coalition is scheduled to hand over control of Iraq to an interim government and troop levels are expected to decrease to about 100,000 from the current 112,000.
"We expect to see an increase in violence as we move forward towards sovereignty," Army Lt. Gen. Ricardo Sanchez, the top U.S. commander in Iraq, said in a frank assessment echoed by L. Paul Bremer III, the civilian administrator.
But U.S. officials point to progress: a drop in daily attacks against coalition forces by more than 50% -- from a high of 55 daily attacks a month ago to 20 today -- as the Army launched several major offensives involving bombing runs, house-to-house searches, enhanced patrols and the encirclement of entire villages with barbed wire.
The Army says improved intelligence gathering, boosted by financial rewards for informers with accurate information about attackers, has resulted in the breakup of several insurgent cells, including the ones believed responsible for the October attack on the Al Rashid Hotel and the roadside assassination last month of seven Spanish intelligence agents.
Yet commanders acknowledge that busted cells have demonstrated an ability to regenerate, replenished by the legions of former Iraqi army officers, disenfranchised Saddam Hussein loyalists and angry young men without jobs reared on anti-Western invective who can earn some cash by attacking soldiers and allies. As strikes against heavily guarded coalition forces have decreased, assaults on "soft" targets -- foreign contractors as well as police officers, public officials and other Iraqis seen as collaborators -- have surged.
"The organizers of these attacks have the money -- and everything in Iraq now revolves around money," said Army Maj. Gen. David H. Petraeus, who heads the 101st Airborne Division in the northern city of Mosul.
A week ago, the Army seized $1.9 million in cash from a suspected insurgent's home in Samarra, a massive sum in a city where the major income comes from Shiite pilgrims to its renowned, gold-domed mosque.
Despite the drop-off in the overall number of attacks, November still featured more coalition fatalities -- 111 -- than any month since the war began in March, in part because of the crash of four U.S. helicopters under fire.
The psychological toll is such that there is a widespread expectation that the recent lull in Baghdad is a prelude to some kind of major insurgent operation -- and there is little that can be done to stop it.
"We either have put a huge dent in their ability to strike in Baghdad," said a senior commander who declined to be identified, his tone revealing some disbelief in that theory, "or they're getting ready for a major attack. It's been too quiet."
Since summer, the insurgents have successfully pushed the front lines beyond the so-called Sunni Triangle in central Iraq to once relatively calm northern cities such as Mosul and Kirkuk, both now awash in attacks and insecurity. Assaults in the largely Shiite south have also thwarted progress and sown uncertainty.
The systematic advance of the insurgent strategy has stunned many U.S. planners, who remain bewildered by the guerrillas' command structure. The walls of Army tactical centers are inevitably filled with charts trying to trace cell members and their links to financiers, known affiliates of Hussein's Baath Party, Fedayeen Saddam paramilitary fighters, hostile sheiks and other suspected subversives.