But by dusk it was unclear what, if anything, had been achieved and fighters from the Mehdi Army, founded by radical Shiite cleric Moqtada Sadr last year, celebrated what they viewed as a small victory.

"There were two American offensives. At 7:00 am (0400 GMT), three tanks advanced. We destroyed one and the others retreated. Three hours later, three came back and we destroyed two," said one militiaman who gave his name as Mustafa, his eyes bloodshot with fatigue.

"We managed to ground a tank, but we can't destroy it because it's in among the tombs," said another fighter as a group of his comrades danced.

"Give us victory oh Lord, in the name of the prophet (Mohammed), (Imam) Ali, Moqtada, give us victory," they chanted.

Neither the US military nor war correspondents covering the fighting could confirm whether any US tanks had been damaged, possibly because the giant cemetery -- one of the largest in the world -- was completely cut off.

There were constant and deafening explosions in Najaf throughout the day. The city was pounded without reprieve. Mortars on top of tank fire. Tank fire on top of mortars as helicopter gunships swooped through the sky.

Brief lulls were shattered by machine-gun and rifle fire.

Over the bombardment, muezzin wailed encouragement to militiamen at the city's sacred Imam Ali mausoleum, once a beacon for Shiite pilgrims all over the world and now a barracks for the Mehdi Army.

"You are fighting for faith and if you die a martyr you will go to paradise where Imam Ali will welcome you. Please God and his prophet!" chanted one, before reciting verses from the Koran.

In the esplanade outside the shrine, a militiaman could only offer cold comfort to his family.

"I miss you all. I want to die a martyr. Look after yourself and the children and the house," he told his mother, before placating a frantic wife, convinced that he was already a dead man.

"I love you and the children so much. Pray that I die a martyr. If I die, sell the car, take 1,000 dollars and give the rest to my mother and brothers," he said.

In the street linking the shrine area to the cemetery, fighters lolled on the pavement, in shops or burrowed down in half-finished building sites, their rocket-propelled grenades, machine guns and Kalashnikovs ready at hand.

At mealtime, a young man started handing out raisons from a plastic bag.

Behind him came others with metal plates carrying rice and meat. "Meat is good for fighting," said one of them, laughing to nods of agreement.

Another man handed out fresh water. Later, there was tea.

Suddenly, a cry of "They're attacking!" was barked out from inside the cemetery, followed by the crackle of semi-automatic gunfire.

The men clatter to their feet to the rallying cry: "Moqtada make the ground tremble under the Americans' feet".

Since the fighting erupted Thursday, when the Mehdi Army attacked the main police station and governor Adnan al-Zorfi requested US support, the US military estimates that more than 360 insurgents have been killed.

But a spokesman for Sadr has insisted that only 15 militiamen have been killed and 35 wounded, the majority from cluster bombs.

WAR.WIRE