The shootings occurred as residents marched through the streets, demanding the withdrawal of American forces from the town.

The demonstration yesterday morning was called by local religious leaders to put pressure on the Americans to leave. Growing tensions with the local population had been aggravated by the shooting on Monday of 13 civilians outside a school that was being used as a military base. More than 1,000 demonstrators were marching yesterday on the former Baath party headquarters in the town, where American troops had taken up their positions, when an armoured patrol tried to force its way past.

Demonstrators say that a brick was thrown at one of the vehicles; American military officials insist that bullets were fired from the crowd.

Whichever was true, jittery forces immediately opened fire on the protesters from their vehicles and from inside the compound, killing two and wounding 12.

The crowd scattered and the wounded were rushed to hospital, but within an hour the protesters had regrouped again outside the compound, baying for the Americans to withdraw as the troops sat behind coils of razor wire, nervously eyeing the crowd.

“There is no God but Allah!” the protesters chanted, sitting in the street, as a fresh convoy of American troops rumbled along the street towards them.

As the tanks approached, the protesters surged forward, screaming at the soldiers and hurling their shoes at the tanks, a grave insult in Islamic culture.

“With our souls and our blood we sacrifice Islam,” they chanted, carrying a local mullah on their shoulders towards the column of tanks.

The tanks screeched to a halt and quickly reversed, crushing a traffic reservation in their haste to reroute. Then the crowd turned their anger on the soldiers stationed inside the compound, shouting: “You are killers. Go, go home!” American military officials blamed infiltrators for the incident, but acknowledged that they may have killed innocent civilians while responding to what they insisted was enemy fire.

“The evil-doers are deliberately placing at risk the good civilians,” Lieutenant-Colonel Tobin Green, of the 3rd Armoured Cavalry Regiment, said. “These are deliberate actions by the enemy to use the population as cover.”

Whatever the background, there is no denying the tensions that exist between the local population and US troops, who moved in only last Friday, supplanting the local security committee’s efforts to keep law and order.

Residents insist that that their opposition to the troops’ presence is grounded in religious belief and not support for Saddam Hussein, despite his previous popularity here.

During his rule, Fallujah was a stronghold of the ruling Baath party and the fall of the dictator has severely threatened the city’s network of privilege and power.

Religious leaders have led the charges against the Americans, accusing them of myriad crimes, from surreptitiously watching local women through their binoculars to distributing pornographic pictures to schoolchildren.

Those charges, however, have been overtaken by the killing and wounding of civilian protesters over the past three days. Residents insist that there were no security problems in Fallujah before the arrival of the Americans and that there is no cause for them to stay.

“The fighting will go on day by day here until the Americans leave,” one protester said, shaking his fist at the gate of the American compound.

Military officials confirmed that about 100 soldiers involved in the first shooting had vacated the primary school compound and had left the city, but they said that no more troops would be withdrawn. The mayor of Fallujah, a former Iraqi exile appointed after the fall of the old regime, said that he had told the Americans not to provoke people by occupying sensitive areas such as mosques and schools for fear of further violence.

“Many people believe these are occupying forces. And many of them are still cautious until they see their intentions,” Taha Bedaiwi al-Alwani said.

He met American officials yesterday to demand an investigation into the shootings and to request compensation for the victims.

Times Recommends

• Michael Jackson: Not the final chapter
• Indian Army spends10m rupees on golf buggies
• Brüno toned down for 15 rating