U.S. Marines are preparing for a decisive battle in the Sunni Triangle area west of Baghdad, where rebels are using violence and intimidation to extend their influence out from the city of Fallujah, senior commanders said Friday.

"We are gearing up to do a major operation, and when we are told to go, we will go," said Brig. Gen. Dennis J. Hejlik, deputy commander of the 1st Marine Expeditionary Force, which is responsible for security in the area. "When we go . . . we're going to go in there and whack them."

Hejlik said the Marines were awaiting orders from Iraq's interim prime minister, Ayad Allawi, to launch an offensive in Fallujah and in Ramadi, the nearby provincial capital. Iraqi security forces and U.S. Army units would also take part in the operation, he added.

"This will be directed by the interim Iraqi government," Hejlik said during a briefing with reporters. "They are calling the shots."

Insurgents have controlled Fallujah since April, when Marines laid siege to the city, but an offensive was called off under pressure from the White House and L. Paul Bremer, the civilian administrator of the U.S.-led occupation authority then in charge in Iraq. Since then, military officials have described Fallujah as a hub of the Iraqi insurgency and the base for Abu Musab Zarqawi, a Jordanian militant who has proclaimed allegiance to Osama bin Laden's al Qaeda organization.

While Zarqawi and other foreign militants have vowed to fight until U.S. and other occupying forces quit Iraq, local insurgents have been negotiating with Iraqi authorities to hand over control of the city peacefully. But Taha Ali, a press officer for Allawi, said Friday that the government was "losing patience" with the discussions.

Allawi favors the "peaceful solution," Ali said, but he added that "this might be the last" chance to accept it.

In Fallujah, about 50 religious leaders met with members of the Shura Council of Mujaheddin, the self-appointed group that governs the city. The council closed the meeting to reporters, but a source familiar with the discussions said the group agreed to issue a fatwa, or religious order, calling for a holy war if U.S. forces pushed into Fallujah.

"War is very close," Abdullah Janabi, the head of the council, said while leading Friday prayers at the Hadhra Muhammadiya mosque, one of the most important in Fallujah.

"The government is responsible for the bloodshed in Fallujah," he said. "We have no choice -- it is either victory or martyrdom."

On a typical Friday, prayers draw more 3,000 men to the mosque. This week, about 200 attended, reflecting the recent exodus from Fallujah. Sabbar Janabi, the police chief, said about 16,000 families had fled. About 1,800 are living in tent camps outside the city, and an additional 2,000 are in school buildings.

Abbar Muhi, 49, covered a burned-out bus outside the city with paper and made it into a shelter for his wife and three children. Muhi said he had to close his auto shop. "We have no food, no money," he said. "We live in hunger."

Kona Aswad, 36, left her home for one of the camps set up west of the city. "We don't have money," she said as she filtered river water through a piece of cloth. "We asked the mujaheddin to help us. They refused. We went to the U.S. forces to ask their help. They investigated us and asked us about Fallujah, but they didn't help us."

In one sign of preparations for battle, Marines at an outpost near Fallujah are no longer getting hot meals three times a day; instead, to conserve food, they get packaged rations for lunch, a Marine spokesman said. The Marines also conducted a gas-mask drill, their first since they took over security duties in western Iraq from the U.S. Army seven months ago.

For weeks, U.S. warplanes have been striking targets in Fallujah believed to be linked to Zarqawi's guerrilla organization. U.S. and Iraqi authorities have blamed Zarqawi and his supporters for many of the deadliest attacks in Iraq in recent months. The U.S. government has offered a $25 million reward for his capture or death.

"Zarqawi is nothing more than a thug who is illiterate," said Maj. James West, a Marine intelligence officer. Ordinary Iraqis "are more scared of Zarqawi because of what he has done" than they are of any government or military force, he said.

West said Fallujah had become a base for foreign fighters who have come to Iraq for jihad, or holy war, against American forces and the Iraqi government. "As long as Fallujah becomes a giant hub, they are starting to push out farther and farther," he said of the insurgents.

Marine leaders said they had no idea how many foreign fighters were in Fallujah. West said some estimates put the force at 5,000, but he was more general, placing the number at "several thousand." He acknowledged that the U.S. military did not know for certain that Zarqawi was in Fallujah.

Eliminating Zarqawi and his network would not stop the insurgency in Iraq, West said, but "if you don't catch him, the insurgency will not stop."

Special correspondents Omar Fekeiki, Khalid Saffar, Bassam Sebti and Naseer Nouri in Baghdad and Saad Sarhan in Najaf contributed to this report.

Iraqi youths cheer as a Turkish transport truck burns in Mosul, northern Iraq. Gunmen killed the driver before setting the vehicle ablaze, witnesses said.