TAL AFAR, Iraq — U.S. Army officers in northwest Iraq, near the Syrian border, say they don't have enough troops to hold the ground they take from insurgents in this transit point for weapons, money and foreign fighters.

From last October to the end of April, there were about 400 soldiers from the 25th Infantry Division patrolling the northwest region, which covers about 10,000 square miles, an area about the size of Maryland.

"Resources are everything in combat ... there's no way 400 people can cover that much ground," said Maj. John Wilwerding, of the 3rd Armored Cavalry Regiment (ACR), which is responsible for the tract that includes Tal Afar.

"Because there weren't enough troops on the ground to do what you needed to do, the (insurgency) was able to get a toehold." said Wilwerding, 37, of Chaska, Minn.

During the past two months, Army commanders, trying to pacify the area, have had to move in some 4,000 Iraqi soldiers; about 2,000 more are on the way. About 3,500 troops from the 3rd ACR took control of the area this month, but officers said they were still understaffed for the mission.

"There's simply not enough forces here," said a high-ranking U.S. officer with knowledge of the 3rd ACR. "There are not enough to do anything right; everybody's got their finger in a dike."

The officer spoke on the condition of anonymity because of concern that he'd be reprimanded for questioning U.S. military policy.

Control of the area is seen as key to stemming the insurgency in the rest of Iraq. More than 650 Iraqis have been killed since the nation's interim government took office April 28.

May turned out to be the deadliest month since November for U.S. troops in Iraq, with 65 reported killed by insurgents, according to figures tabulated by Iraq Coalition Casualty Count, a group that tracks coalition troop deaths from Department of Defense releases.

"This town is kind of like a staging point for the rest of the country," said Capt. Geoff Mangus, 25, of Milledgeville, Ga., an Army intelligence officer in Tal Afar. "They know that weapons and foreign fighters can filter through here unscathed."

Army officials in northwest Iraq described a two-year cat-and-mouse game with insurgents who move from one outpost or town to the next, sustaining casualties but buoyed by an influx of fighters slipping across the Iraq-Syria border, which, in many places, isn't patrolled. From their sanctuaries, the fighters spread out, some volunteering to be suicide bombers.

They funnel cash, arms and recruits to the insurgency, Mangus said. Repeated efforts to secure the area have failed.

In Tal Afar, the police — with only 150 officers left in what was a 600-man force — are holed up in the only remaining police station. Insurgents destroyed three others last year. To the west, the mayor and police have abandoned the town of Bi'aj. To the south, in Rawah, a recent patrol found no evidence of the mayor, police or "rule of law," said Maj. Bryan Denny, 38, of Oxford, N.C.

Military commanders said they planned to reinstall police squads and governmental leaders where possible, to keep insurgents from overrunning the towns.

They've tried that before. U.S. forces retook Tal Afar from insurgents last September after a two-week blockade, airstrikes and street combat. The top U.S. officer in the area, Brig. Gen. Carter Ham, predicted then that the 250,000 residents of Tal Afar would be back on their feet soon.

More than eight months later, insurgents still launch daily sniper and mortar attacks. Car bombings in the town killed 40 people and wounded 80, at a minimum, in May. Two helicopters have been forced to land because of hostile fire during the past week.

Sectarian and tribal tensions also have increased, putting U.S. soldiers in the precarious position of navigating bloody disputes between warring factions with their own conflicting agendas and further straining resources.

A group of about 25 U.S. soldiers and 100 Iraqi soldiers has moved into a Tal Afar neighborhood to separate two warring tribes. The Americans said one tribe was pro-insurgent and was targeting the other because it was pro-American. Others said the tribes — one is Sunni Muslim and the other Shiite — were fighting over jobs and territory. The mayor is suspected of sympathizing with the insurgents.

"What the insurgents want to do, what the terrorists want to do, is incite ethnic and sectarian violence," said Col. H.R. McMaster, 42, of Philadelphia, who commands the 3rd ACR.

"The danger that all of us are concerned about is that these communities will fall in on themselves," McMaster said.

"If the tribes cannot work together, if they cannot make a deal, we can be here 20 more years and do nothing," Brig. Gen. Mohsen Doski, the commander of the Iraqi army brigade in Tal Afar, told 3rd ACR Lt. Col. Chris Hickey, as the two spoke about how to deal with the violence in Tal Afar.

U.S. troops and military officials in the embattled Anbar province said in recent interviews with the Los Angeles Times that they had neither enough combat power nor enough Iraqi military support to mount an effective counterinsurgency against an increasingly sophisticated enemy.

"You can't get all the Marines and train them on a single objective, because usually the objective is bigger than you are," said Maj. Mark Lister, a senior Marine air officer in Anbar province. "Basically, we've got all the toys, but not enough boys."

The Pentagon has made training Iraqi troops its top priority since Iraq's national election in late January. But in Anbar province, that objective is overshadowed by the more basic mission of trying to keep much of the region out of insurgent hands.

Just three battalions of Marines are stationed in the western part of the province, down from four a few months ago. Marine officials in western Anbar say each of those battalions is smaller by one company than last year, meaning there are approximately 2,100 Marines there now, compared with about 3,600 last year.

Some U.S. military officers in Anbar province say commanders in Baghdad and the Pentagon have denied their repeated requests for more troops.

"(Commanders) can't use the word, but we're withdrawing," said one U.S. military official in Anbar province, who asked not to be identified because it is the Pentagon that usually speaks publicly about troop levels. "Slowly, that's what we're doing."

Such reductions are especially problematic because U.S. commanders have determined the insurgency's "center of resistance" has shifted to the western part of the province. The insurgency's base of operations was once the eastern corridor between Fallujah and Ramadi. Now, Pentagon officials say, it is in villages and cities closer to the Syrian border.

Information about Anbar province operations from the Los Angeles Times