Iraq's most influential Shia cleric made a sudden return to the country today and urged Iraqis to march on the "burning city" of Najaf, where fighting is edging closer to its holiest shrine.
The call from Grand Ayatollah Ali al-Sistani, a moderate who has said little about a crisis that has killed hundreds, could sharply escalate passions among the majority Shia community.
Aides said Sistani arrived in the southern city of Basra from Kuwait, having undergone heart treatment in London for three weeks. Tomorrow he is to travel to Najaf, his adopted home.
The news of Sistani's return came as US and Iraqi forces tightened their grip around Mahdi Army militants loyal to radical cleric Moqtada al-Sadr, who have holed up in Najaf's Imam Ali mosque, advancing to within 300 metres of the rebel-held shrine.
Aide Hamed al-Khafaf said Sistani wanted to save the city. "Najaf is burning. Ayatollah al-Sistani is on his way back and calls on Iraqis from all provinces to join him in the holy city," Mr Khafaf said by telephone from Beirut.
The logistics of the march would be known shortly, he said. Another aide said the militia should leave the mosque and US forces not interfere.
Sistani (73) reached Basra from Kuwait in a convoy of more than a dozen vehicles led by police cars with sirens wailing.
His departure for London coincided with the outbreak of the rebellion by the militia of Sadr, a young cleric who has challenged the collegiate leadership of the Najaf clergy led by the elder Sistani.
The call to march appears to be an attempt by the Iranian-born cleric to reclaim some of the political ground captured during the uprising by Sadr, who has painted himself as the face of anti-US resistance and icon to the poor masses.
Sadr aide Mahmoud al-Soudani told Al Arabiya television the Mahdi militia were prepared to talk to halt the fighting, which has undermined the authority of interim Prime Minister Iyad Allawi and rattled world oil markets.
"We are ready to respond to any call from Sayed Sistani or anyone else to stop the bloodshed," he said. Sadr also called for his own followers to march on Najaf.
In the heart of Najaf's old city, US tanks fired shells and troops advanced closer to the mosque as US helicopters fired on militia targets. But a threatened assault on the shrine has not yet gone ahead.
Gunfire rocked the area and smoke rose into the sky. Asked if the US military would suspend operations following Sistani's return, US Rear Admiral Greg Slavonic said: "The Iraqi leadership is leading this effort ... We will follow whatever course of action the Iraqi leadership decides."
Iraqi Defence Minister Hazim al-Shalaan had warned the Mahdi fighters they would be "wiped out" if they did not leave the mosque by yesterday evening. US and Iraqi officials have said only Iraqi forces would storm the mosque.