Iraq’s ruling Shia alliance accused the Americans of trying to foment civil war today after a joint US-Iraqi raid on a Baghdad mosque in which 16 people were killed.

The US military said that the raid, by Iraqi special forces backed up by US advisers, had targeted a terrorist cell. It denied that troops entered the mosque.

Iraqi ministers have however accused the troops of tying worshippers up before shooting them in cold blood. One minister put the death toll at 37.

The row overshadowed a suicide bomb attack that killed 40 men queueing up outside an army recruitment centre near the northwestern city of Mosul. That "blessed operation" was claimed by a group affiliated to al-Qaeda, which said that it had been carried out by a Saudi volunteer.

As angry Shia Muslims buried those killed in last night's operation in the northeast of Baghdad, the United Iraqi Alliance (UIA), the Shia coalition which holds the largest number of seats in the new parliament, condemned the raid.

Jawad Maliki, number two in the Dawa Party of Ibrahim Jaafari, the Prime Minister, read a statement which said: "US forces and Iraqi special forces committed a heinous crime by attacking the Mustafa mosque in the neighborhood of Ur. It is a serious crime with grave political and security implications which aims to provoke civil war in the country.

"Killing a large number of followers of the Prophet’s house after having bound and tortured them is unjustifiable. It is an attack on the dignity of the Iraqis and destroys the credibility of slogans of liberty and democratic and pluralism brandished by the US administration."

The alliance also demanded that the Government open an investigation into the raid, and that control of security matters be handed back to Iraqis.

The raid has highlighted divisions within Iraqi security forces. The special forces involved report to the Defence Ministry, which is run by a Sunni Arab. By contrast, the police report to the Shia-run Interior Ministry, which Sunnis accuse of encouraging Shia death squads which murder prominent Sunnis..

"The government must also find out the truth about these special units in the Iraqi army that function outside the control of the government and perpetrate massacres with support from the US army," the UIA statement added. "The existence of these forces, if it is confirmed, is another element contributing to civil war."

In a statement, the US military said: "Iraqi Special Operations Forces conducted a twilight raid in the Aadhamiya neighbourhood in northeast Baghdad to disrupt a terrorist cell responsible for conducting attacks on Iraqi security and Coalition Forces and kidnapping Iraqi civilians in the local area.

"No mosques were entered or damaged during this operation."

At the burials of the mosque victims in Baghdad, men wailed and hugged each other as some coffins were loaded onto vans. Furious mourners said that only the Mahdi Army, the militia loyal to the radical Shia cleric Moqtada al-Sadr, could protect them.

Violence between Shia Muslims and minority Sunni Arabs, who were favoured under Saddam Hussein’s rule, has been rising. Many Iraqis fear the bloodshed could spiral into all-out civil war.

Police said that they had found the strangled, tortured bodies of 12 more apparent victims of sectarian feuding in Baghdad today. But scores of such corpses turn up in Iraq every day and the discovery of 30 headless bodies in a village northeast of Baghdad yesterday was barely reported in local newspapers.

Although the facts of last night's raid were in dispute, analysts said that it would be a propaganda windfall for Hojetoleslam al-Sadr, feeding on Shia concerns that America could abandon Iraq as it did after the first Gulf War, when Saddam Hussein brutally crushed Shia and Kurdish uprisings.

Meanwhile, Saddam’s former lieutenant, Izzat Ibrahim al-Douri, called on Arab leaders to support the insurgency and boycott the government in an audio tape aired by the al-Jazeera television network.

Ibrahim was sixth on the US deck of cards that enumerated the most-wanted members of Saddam’s regime. He had been vice-chairman of the Revolutionary Command Council and was a long-time confidant of Saddam.

Iraq has been convulsed by waves of tit-for-tat sectarian killings since the bombing of a famous Shia mosque in Samarra, north of Baghdad, on February 22. Many of the killings have been blamed on Shia militias acting with the collusion of the Shia-led government.

But Ibrahim - who has been credited with a major role in organising the Sunni insurgency, which has ruthlessly targeted Shias - condemned the attacks on Shia mosques and holy sites.

He said: "O faithful mujahideen, know that the bombing of the dome of ... Imam Ali and the killing of Iraqi innocents and civilians and the burning of mosques, Shia holy sites and churches, and killing based on identification cards represents the epitome of vileness, vice and a crime. And our people and resistance will take revenge on the perpetrators sooner or later."

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