'Hundreds killed' in the bloody battle of Najaf

American forces claimed yesterday to have killed 300 Shia insurgents in Najaf over two days of some of the most intense fighting since the end of the war against Saddam Hussein's regime 16 months ago.

The battle - which raged at its bloodiest in Najaf but also spread to Shia areas elsewhere in Iraq - marked the shattering of the fragile truce that two months ago had ended a previous uprising led by the Shia cleric Muqtada Sadr.

No independent corroboration could be made of the death toll, which was given by the US Marines at their forward operating base 30 miles outside the Shia holy city. Lt-Col Gary Johnston, operations officer for the 11th Marine Expeditionary Unit, declared: "That is our estimate; that is our assessment." He did not give any estimate of civilian casualties.

Smoke rose from the old city in the centre of Najaf after helicopter gunships attacked insurgents said to be hiding in a cemetery close to the sacred shrine of Imam Ali. Footage on Associated Press Television News showed roadside stalls burning as shops closed, leaving many streets deserted. A woman's body was shown abandoned on an empty footpath.

The fighting came as the most revered Shia cleric, the 73-year-old Ayatollah Ali al-Sistani, a potentially moderating influence, was flown to London so a heart condition could be treated. His relatively infrequent public pronouncements have tended to urge peaceful means towards achieving change. He was prominent in calling for early elections.

US military sources said that two US Marines and an American soldier had been killed in the fighting, and that 15 soldiers had been wounded on Thursday and early yesterday during engagements with insurgents in Baghdad's Shia suburb of Sadr City. The Iraqi Health Ministry said 19 people had been killed and 111 wounded there.

While a spokesman for Sadr denied the US estimate of the death toll in Najaf - putting it as low as 36 - another official with the insurgency leader's office in the city said: "The area near the [Imam Ali] shrine is being subjected to a war. Najaf is being subjected to total destruction. We call on the Islamic world and the civilised world to save the city."

Each side blames the other for starting the violence. Both the Iraqi interim government and US forces are adamant that the fighting started when Sadr's Mehdi Army insurgents attacked a police station in the early hours of Thursday. Lt-Col Johnston said that the attack was repelled by Iraqi forces until the insurgents regrouped two hours later. Overwhelmed, the governor of Najaf had asked for US reinforcements.

At first, the fighting had subsided, Lt-Col Johnston said, but between 7 and 8am another force, "several hundred strong", had massed in the cemetery. He added: "Some of our forces were down there still and that is how the situation started escalating."

Sadr's spokesmen insist the truce was broken when US forces surrounded the cleric's home earlier in the week - a claim denied by senior US officers who say they had not been seeking to detain Sadr, officially wanted in connection with the murder of a rival cleric.

The fighting also spread to the south, and in Nasiriyah Italian troops came under fire. According to Interior Ministry officials, eight Iraqis, including five militants, were killed and another 13 were wounded.

Iraq's second city, Basra, under British control, was also tense. As'ad al-Basri, a spokes-man for the Sadr insurgents, said that five Mehdi Army members had been killed in engagements with British troops.

In Samarrah, a Sunni stronghold 60 miles north of Baghdad, a US convoy of 10 Humvees reportedly pulled out under cover of helicopter fire after coming under attack.