Sunni Resistance to U.S. Presence Hardens

The fighters and their leaders have more or less run Fallujah since the truce was arranged in early May. As a result, U.S. military officials have expressed worry that Fallujah may become -- or perhaps already has become -- an incubator for insurgency recruits.

The Fallujah Brigade, a security force under the command of former Iraqi army officers, was supposed to take control of Fallujah in early May in collaboration with the U.S. Marines. Instead, it has ceded authority to a sort of commune that has sprung up in recent weeks, guided by the Mujaheddin Advisory Council under the leadership of the town's senior Sunni cleric, Sheik Abdullah Janabi, and his main lieutenant, Sheik Dhafer Obeidi.

L. Paul Bremer, who was the U.S. administrator in Iraq until the transfer of political authority on June 28, arranged as one of his final acts to have warrants issued for the arrest of Janabi and Obeidi, according to Mutlak and Baghdad news reports. If U.S. troops tried to take the two Sunni clerics into custody, Mutlak predicted, Fallujah would erupt into even greater violence.

A similar order against Sadr in April touched off the weeks-long confrontation between the cleric's Mahdi Army militia and U.S. troops in the Najaf area, about 90 miles south of the capital. Mutlak said that episode showed that U.S. authorities are mistaken in confronting insurgent fighters rather than seeking to negotiate with them.

Allawi, the interim prime minister, while speaking out sharply against attackers, has also indicated a conciliatory attitude. His spokesman, Georges Sada, told reporters the government was working out an amnesty for resistance fighters who had not been involved in attacks that qualified as terrorism. In addition, Allawi has spoken of bringing former Baath Party and Iraqi army officials into the new system, in effect abandoning the de-Baathification program put in place by Bremer.

Many former intelligence agents and military officers have formed cooperative relationships with Islamic insurgents in Fallujah and elsewhere, even though Hussein's Baath Party was, in principle, secular. Their expertise in such areas as explosives and arms has boosted the firepower of insurgent organizations.

U.S. officials have speculated that former government officials might also still have access to money to help finance attacks. The most senior official from Hussein's regime still at large is Izzat Ibrahim, who specialized in internal security.

After Fallujah, the other main insurgency stronghold is Baqubah, a farming town 35 miles northeast of Baghdad. Residents there, as in much of the swath of central Iraq known as the Sunni Triangle, had strong ties to Hussein's Baath Party.

Successive U.S. Army units stationed in Baqubah have had particular trouble in Buhris, a village on the edge of the city where tribal sheiks were traditionally courted and paid off by Hussein's government. The web of tribal loyalties woven by Hussein's intelligence services around Baqubah has been difficult to pierce for U.S. military officers, whose men for months were shot at every time they entered Buhris.

Baqubah residents have said gunmen from elsewhere have also played a role in the violence there. Fighters proclaiming loyalty to Zarqawi were seen in the streets of Baqubah during the last eruption of large-scale fighting there on June 24.

"It's from outside," said Ali Abdul Kareem Madani, the senior Shiite Muslim cleric in Baqubah.

Baghdad itself, often a target of the bombings, was also discovered recently to be the site of several facilities where car bombs were being assembled and rigged into vehicles. About 50 people were arrested and bomb-making equipment was seized in a series of raids reported Saturday by the U.S. Army's 1st Cavalry Division.

One of the deadliest recent attacks, a series of car bombings in Mosul on June 24, was attributed to Ansar al-Islam, a small group in northern Iraq formerly associated with Zarqawi. The explosions, targeting Iraqi police buildings, killed more than 80 people in the city, 220 miles north of Baghdad.

Abdul-Jabbar said Ansar al-Islam was one of several names used by Zarqawi and his foreign or Iraqi followers. Others cited on Islamic Web sites include the Monotheism and Jihad Group, the Ansar al-Sunna Army and the Sharp Sword Against the Enemies of God and His Prophet, all of which have asserted responsibility for taking foreign hostages and in some cases beheading them.