Some U.S. officers believe tribal leaders have heeded warnings and used their influence to curb attacks against Americans in Fallujah (search). Others cite the arrests of key resistance figures or the holy month of Ramadan (search).

Whatever the reason, this "Sunni Triangle" (searchcity, which had been among the most dangerous in Iraq for U.S. soldiers, has been uncharacteristically quiet since insurgents near here shot down a Chinook (searchtransport helicopter Nov. 2, killing 16 Americans.

Deeply conservative and anti-American, Fallujah has a population of some 200,000, all of whom are members of Islam's mainstream Sunni Muslim sect. Some subscribe to radical interpretations of Islam, finding behavior by American troops like raiding homes and detaining men in front of wives and children as deeply offensive.

"Fallujah is a very, very complex place," said Lt. Col. Brian Drinkwine, the senior U.S. officer here. "Every time you peel back a layer you are faced with a new set of problems."

Drinkwine and his paratroopers of the 1st Battalion, 505th Parachute Infantry Regiment of the 82nd Airborne Division arrived in Fallujah in early September. Days later, the paratroopers mistakenly killed eight Iraqi policemen and a Jordanian security guard in a friendly fire incident.

In April, other division troops killed 18 Iraqis and injured scores when they fired at protesters on two successive days.

In both incidents, the U.S. military says, the American soldiers were shot at first.

The killings, however, sparked an upsurge in attacks against U.S. troops in Fallujah. Television footage of burning U.S. vehicles and crowds dancing to celebrate attacks gave the city the appearance of a war zone.

Drinkwine's men responded to the attacks by using overwhelming firepower, putting more patrols on the streets and raiding homes in search of weapons and suspected fighters.

"Fallujah must become a secure and stable environment," said Maj. Gen. Charles H. Swannack Jr., commander of the 82nd Airborne Division. "Fallujah affects Baghdad and Baghdad is very important to Iraq." Fallujah is 30 miles west of the Iraqi capital.

Three weeks ago, Drinkwine said, a breakthrough was made when his men detained two former generals in Saddam's army thought to be among resistance leaders.

About the same time, a man believed to be the resistance's main bomb maker in the city was apprehended. Attacks have begun to decline since, Drinkwine said.

Fallujah is known to have the most number of mosques for its population in Iraq, a sign of its religious character. Women rarely venture out, and those who do are covered head-to-toe. Restaurants have prayer rooms.

U.S. commanders say their attackers are Saddam loyalists, former Baath party members, Muslim extremists and a small number of foreign fighters.

Fallujah residents say religion is the main motive behind attacks, not loyalty to Saddam or the Baath party.

Like other cities in the Sunni-dominated area, Fallujah benefited from Saddam's 23 years in power. The former dictator, himself a Sunni, recruited his elite Republican Guard officers and brutal security agencies from Iraq's Sunni minority.

Graffiti in the city threatens "collaborators" with death and vows to fight on until the Americans leave. Inscriptions praise Saddam.

The U.S. military has been fighting the resistance on another level, too.

Two weeks ago, the city's police chief was fired for incompetence and failure to effectively fight corruption within his force. On Thursday, Drinkwine persuaded the city's mayor, Taha Bedawi, to step down after seven months on the job.

"Mayor Bedawi forgot that his position was the leader of Fallujah and not just a particular sheik," said Drinkwine, from Massena, N.Y. Drinkwine plans to expand the U.S.-backed city council to include clerics and professionals in an effort to widen its popular appeal and break the monopoly of sheiks over decisions. The move also appeared to reflect dissatisfaction with the role played by sheiks.

Local Fallujah sheiks have been at the heart of the U.S. military's policies in Fallujah since its capture in April. Commanders from the 3rd Armored Cavalry Regiment, the 3rd Infantry Division and the 82nd Airborne -- units that took turns at being in charge of the city -- relied heavily on the sheiks for advice and getting the message to the people at a time human intelligence was scarce.

But U.S. commanders found that their men were coming under more attacks outside the city where the sheiks wielded influence than inside Fallujah, where mosque imams and clerics have the ears of many.

They also speak privately of important sheiks trying to exploit their contacts with the Americans to promote their business interests or gain leverage over rivals.