Sistani arrives in Najaf

A TV image of a wounded Iraqi man in a hospital in Kufa after a mortar attack killed 27 people
Iraq's most senior Shia cleric, Grand Ayatollah Ali al-Sistani, today entered the besieged city of Najaf on a day that saw bloody attacks on the supporters of his young rival, the radical Moqtada al-Sadr.

In nearby Kufa, a mortar attack on supporters of Mr Sadr in a mosque killed at least 27 people, with a further 20 shot dead on the road to Najaf.

Iraq's health ministry said 74 people had been killed in and around the holy city today. A Najaf hospital worker told Reuters: "Go and look at the morgue - it's full."

Mr Sistani yesterday returned to Iraq following treatment for heart trouble at a London hospital in an attempt to broker a deal that would end Mr Sadr's rebellion after almost three weeks of fighting.

The 73-year-old cleric tonight began peace negotiations to persuade Mr Sadr to remove his fighters from the Imam Ali mosque in return for the US forces encircling the complex - one of Shia Islam's holiest shrines - withdrawing from the city, Al Arabiya television reported.

A moderate who commands the respect of most of Iraq's Shia Muslims, Mr Sistani arrived in a convoy of 50 police cars and 10 British military vehicles from Basra to what Luke Harding, the Guardian's correspondent in Najaf, described as a tense welcome.

"It was a cavalcade of people on scooters, minibuses and even a coffin on the back of a car pursuing him into the centre of Najaf," he said.

"[But] the mood here today in Najaf is extremely tense and febrile. Shortly after Sistani arrived, the Iraqi police opened fire on a crowd. I saw two people carried away to an ambulance."

Television pictures of the Kufa mosque attack showed dozens of wounded men lying on the ground in pools of blood as others were ferried to hospital. Survivors chanted angry slogans.

Supporters of Mr Sadr, who had gathered at the mosque prior to a march, blamed US-led forces for the attack. The US military had no immediate comment.

"We were gathering outside and inside the mosque preparing to head to Najaf when two mortar shells landed - one inside the mosque and the other on the main gate," Hani Hashem, who was bringing an injured friend to the hospital, said. "This is a criminal act. We just wanted to launch a peaceful demonstration."

Mr Sistani had also called on his supporters to march on Najaf, but today urged them to wait outside the city. His peace plan envisages Iraqi police taking charge of security and the imposition of a ban on weapons.

The interim Iraqi prime minister, Ayad Allawi, said Mr Sadr had indicated that he would accept all elements of Mr Sistani's plan. Both Mr Allawi and US commanders ordered their forces to observe a 24-hour ceasefire in order to allow the talks to go ahead.

Harding, however, said he was not hopeful that the truce would hold. "The situation here is chaotic and fluid, so it is very hard to know what is going to happen next," he added.

"With the deal comes the stark warning that, if the Mahdi army do not vacate the shrine, military operations will resume within 24 hours and, in effect, the battle will be back on again."

The 31-year-old Mr Sadr has challenged the collegiate leadership of the Najaf clergy, which is headed by Mr Sistani, and presented himself as the face of anti-US Shia resistance.

The cleric has proved himself a stubborn opponent of Iraq's US-backed government. US firepower and peace offers from Mr Allawi - including the promise of a political role and amnesty for his fighters - have failed to move his supporters from the mosque.