A barrage of rockets and mortar rounds exploded in the mainly Shia Karada neighbourhood in east Baghdad, killing 31 people and wounding 153. The attack yesterday came soon after President George Bush agreed to rush more US troops to Baghdad to try to bring sectarian violence under control.
The shells were followed by a car bomb that destroyed a bank and an apartment and set shops on fire in Karada, which is a tight-knit trading area hitherto little affected by violence. Many leading Shia politicians and President Jalal Talabani live in or near the district.
The use of US troops shows the desperation of Nouri al-Maliki’s government to try to regain control of the capital but it is likely to be seen by many Shia – and particularly the main Shia militia, the Mehdi Army – as a move in support of the Sunnis. In some Sunni districts such as al-Amariya and al-Khadra in west Baghdad, people are so frightened they may welcome the American forces.
If the US army does confront the Mehdi Army, it could soon find itself at war with the Shia community in Sadr City, the great Shia bastion in Baghdad with a population of two million, just as the Israelis are at war with Hizbollah in Lebanon.
It is unlikely, however, that some 10,000 US troops will succeed in restoring civil order, something that 50,000 Iraqi forces in the city have failed to do. Sunni now shoot at police and police commando detachments, regarding them as officially sanctioned "death squads".
In many cases, they will only allow them to enter their districts if accompanied by US soldiers. In the historic Sunni al-Adhamiyah district in east Baghdad demonstrators demanded a week ago that a largely Shia army unit be transferred out of the area and replaced by a Sunni battalion.
The sectarian warfare between the two communities is conducted in a different manner by the two sides with the Shia, often policemen, detaining Sunnis and killing them elsewhere. Sectarian killing by the Sunni more often involves suicide bombs or car bombs in crowded markets and mosques. Police discovered a total of 19 bodies, many of them tortured, in Baghdad overnight.
The US forces have already started arresting Mehdi army leaders and fighting Shia militia detachments. But these are often seen by the Shia as essential self-defence forces necessary to safeguard them from pogroms by the Sunni.
There is also a suspicion among the Shia that the US has a long term intention to prevent them, although they are 60 per cent of the Iraqi population, from ruling the country.
The US has fought the Mehdi Army twice in 2004 and said it was trying to kill or capture its leader Muqtada al-Sadr. But Mr Sadr is far more powerful than he was two years ago. He is also popular with his followers, who hold 30 seats in the 275-member parliament and control five ministries including health and transport.
The US says it wants to reduce the power of the militias. "If you don’t do this, you end up with a situation like you have in Lebanon, where the militia becomes a state within a state," said the top US commander in the Middle East, General John Abizaid. "It makes the state impotent to be able to deal with security challenges."
But in practice the US is only going after selected militias, such as the Mehdi Army, which is hostile to the US.