BAGHDAD, Dec. 5 -- A series of large military offensives over the past few months culminating in the battle for Fallujah has given U.S. military commanders here a sense of having gained ground against Iraq's fierce insurgency, but they predict no easy victory in pressing the attack and remain particularly concerned about a rising campaign of intimidation.
Indeed, senior officers say they regard the militants as still well armed and well financed, and likely to avoid trying to mass anywhere again after losing their primary stronghold in Fallujah. The officers say they expect the insurgents to engage in more decentralized operations and sporadic attacks while stepping up threats and violence against Iraqis who serve in the government or the security forces, or who otherwise cooperate with Americans.
"We do believe their tactics are going to change some," said Army Brig. Gen. John DeFreitas III, the top U.S. military intelligence officer in Iraq. "They will probably not mass forces again. They'll fight in small teams. We get some sense that they're thinking of adopting more guerrilla-type tactics -- small teams, hit-and-run."
On Sunday, insurgents killed 17 Iraqi civilians as they arrived for work at a job site run by the U.S. Army near the city of Tikrit, the military said. Four Iraqi soldiers and National Guardsmen were killed in two other attacks in north-central Iraq.
The dispersion and guerrilla tactics of the militants, U.S. officers say, will draw U.S. forces into more classic counterinsurgency operations characterized by focused raids, along the lines of the recent sweep through the northern part of Babil province led by U.S. Marines. Such troop-intensive operations are the reason behind the decision announced last week to boost U.S. forces in Iraq to 150,000.
But while the U.S. military has plans to pursue militants as they attempt to regroup, commanders appear frustrated by their inability to defeat the intimidation. An internal assessment of the U.S. strategy in Iraq, prepared for Army Gen. George W. Casey Jr., the top U.S. commander in Iraq, concluded last week that "no silver bullet" exists for this problem.
The intimidation effort is blamed for undermining the development of effective Iraqi security forces, particularly local police, as well as inhibiting Iraq's interim government, restricting economic development and generally fueling perceptions of insecurity.
Baathists Arouse Suspicion
A total of 338 Iraqis associated with the new governing structures or with the Americans have been assassinated since Oct. 1, according to U.S. military figures. This includes 35 police chiefs, mayors and middle-ranking officials. In Mosul, where 136 bodies have been found in the past month, U.S. officers suspect a particularly brutal and extensive campaign by fighters from the once-ruling Baath Party to target members of the Iraqi security forces.
"Having so far failed in its plan to 'decapitate' the Iraqi interim government, the insurgency appears to be concentrating instead on 'hollowing it out,' " the report to Casey said.
Polling data collected by the U.S. military show that public confidence remains fragile, and many Iraqis have yet to commit decisively to legitimate government, according to officers familiar with the surveys.
Nonetheless, senior U.S. commanders here remain convinced that their military, political and economic strategies for Iraq are still sound, according to interviews with more than a dozen generals in recent days.
The officers said they have been heartened by evidence of greater security and stability in Iraq's southern, Shiite-populated provinces since the assault in Najaf in August against the militia of radical cleric Moqtada Sadr. They also described moves toward next month's elections as generally on track, with more than 200 political entities certified and voter registration proceeding in most of the country. The notable exceptions are the Sunni-dominated provinces of Anbar, which includes Fallujah and Ramadi, and Nineveh, which includes Mosul.
"This is a fight, and in fights you have good days and bad days," Casey said in an interview. "But you don't measure success a day at a time. It's a constant process of going forward and, at the same time, keeping a lookout for what's going wrong."
As a sign of the damage done to the insurgency by the Fallujah operation, U.S. officers point to a sharp decline in the number of attacks nationwide, from a high of more than 130 a day at the start of the offensive in early November to about 60 now. But U.S. military intelligence officers expect the number to rise again before the national elections set for Jan. 30.