The latest shoot-out between US forces and the Sadr militia has prompted an alliance between Sadr and his longtime rival in the Shiite movement, the Iran-backed Supreme Council for Islamic Revolution in Iraq (SCIRI), which controls the equally formidable Badr militia. This will, of course, increase the pressure on Washington to effect "regime change" in Iran... From The Guardian, March 28:

Senior ministers from the three main Shia factions united yesterday to denounce an American raid on a Baghdad mosque complex in which at least 20 people died, opening the biggest rift between the US and Iraq's majority Shia community since the toppling of Saddam Hussein.

"At evening prayers, American soldiers accompanied by Iraqi troops raided the Mustafa mosque and killed 37 people," said Abd al-Karim al-Enzi, the security minister, who belongs to the Dawa party of the prime minister, Ibrahim al Jaafari. "They [the victims] were unarmed. They went in, tied up the people and shot them all. They did not leave any wounded."

Baghdad's governor, Hussein Tahan, a member of the rival Supreme Council for the Islamic Revolution of Iraq (Sciri), announced that local officials were ending their contacts with the Americans in protest at the killings. "The Baghdad provincial council has decided to stop dealings in regards to services and politics with the coalition forces because of the cowardly attack on the mosque," he said.

The interior minister, Bayan Jabr, also of Sciri, who has been strongly criticised by the US embassy for his links with Shia militias, told Al-Arabiya TV: "Entering the mosque and killing worshippers was a horrible violation. Innocent people inside offering prayer at sunset were killed."

Exactly what happened on Sunday night is in dispute, but in a political sense it no longer matters. Tension between the Americans and Shia leaders had been rising for weeks, since Washington started pushing for Mr Jabr's replacement as police minister and went on to oppose Mr Jaafari remaining as prime minister.

The Americans insisted yesterday that they had raided the complex after receiving intelligence that it was being used to hold hostages, store weapons and harbour insurgents. "In our observation of the place and the activities that were going on, it's difficult for us to consider this a place of prayer," said Lieutenant Colonel Barry Johnson, a spokesman. "It was not identified by us as a mosque... I think this is a matter of perception." A brief US communique in the first hours after the incident said "no mosques were entered or damaged".

At the mosque complex yesterday there was a large hole in the door of the prayer hall. A grenade lay on the floor. The wall of the imam's house next door had been blasted open. Rooms were bloodstained and four cars were burnt out.

"Just before prayers at 6.15, we were surprised by US and Iraqi national guards raining fire on us. Anyone who went out was shot dead," Ihssan Kamel Ali, who was in the mosque at the time, said yesterday. "The national guard came in first, then the Americans. They had a man with a Lebanese accent with them. He sneered at us and said what we were reading was not the Qur'an. I heard sounds of explosions. I saw between 17 and 20 bodies. What upset me most was that there was a wounded man. An Iraqi soldier asked an officer what to do with him. The officer said 'Just finish him off'."

Iraqi police identified seven of the dead as members of the Mahdi army, a militia formed by the radical cleric Moqtada al-Sadr. Salam al Maliki, the transport minister who heads a group of 30 MPs loyal to Mr Sadr, said Shia leaders suspended discussions yesterday on forming a new government in protest at the assault.

In another setback, a suicide bomber attacked a joint US-Iraqi base near Tal Afar in northern Iraq. The explosion killed 40 Iraqis, according to the defence ministry, most of them would-be recruits queuing to be registered. No Americans died.

See our last post on Iraq.