An entire police brigade in Baghdad has been suspended and its commander placed under arrest on charges of aiding sectarian death squads that have carried out mass kidnappings, it emerged today.

The Eighth Brigade of the 2nd National Police Battalion, created to keep order in western Baghdad, was de-mobilised a day after armed men in uniform herded off 14 shopkeepers from central Baghdad, and two days after 24 workers were abducted from a meat processing plant in the capital.

"The brigade’s past performance does not demonstrate the level of professionalism sought by the ministry of the interior," Major General William Caldwell, of the US military, said.

"It was realised that removing them from Baghdad would, in fact, enhance security." The brigade has more than 800 officers in uniform.

"There was clear evidence that there was some complicity in allowing death squad elements to move freely, when in fact they were supposed to be impeding their movement," General Caldwell said.

"The forces in the unit have not put their full allegiance to the government of Iraq and gave their allegiance to others," he added.

Sunni leaders have for months accused police units of helping Shia death squads carry out a series of massive kidnappings, which have included the abduction of the entire US-Iraqi Chamber of Commerce, several groups of factory workers and the Iraqi Olympic Committee.

They have charged that the police forces are hopelessly infiltrated by members of Shia militias who have killed scores of innocent people.

Brigadier Abdel Karim Khalaf, an interior ministry spokesman, said the lieutenant colonel in charge of the Eighth Brigade had been detained and was being questioned, while rank-and-file policemen were being investigated at random.

The charges of complicity in the sectarian war that has crippled the capital was a further admission by the Shia-led government that its own security forces are partly responsible for the incessant violence plaguing Baghdad.

Nouri al-Maliki, the Iraqi Prime Minister, announced yesterday a four-point plan that included the establishment of neighbourhood committees who would be able to report on suspicious activities by the security forces and local militias.

The disgraced brigade will be sent for re-training by American forces, although one US trainer said the training programme had been scheduled months ago as part of a sweeping overhaul of Iraq’s police forces, who were hastily recruited after the 2003 invasion and which have frequently proved inadequate to the task of eradicating violence.

In late 2004, almost the entire police force in the northern city of Mosul fled their bases when insurgents attacked, while Shia policemen in Najaf joined rebels from the Mahdi Army militia and gave them their weapons when they took over the shrine city earlier that year.

Since those major setbacks, US forces have been re-training the Iraqi police, but the programme has had little impact.

A survivor of Monday’s mass kidnapping in a parade of computer shops near Baghdad’s Technology University described how half a dozen vehicles, with official security forces markings on them, pulled up and men in military fatigues rounded up all the Sunnis in the shops. They drove off with 14 people but stopped two shops short of his establishment, he said.

The bodies of several of those abducted from a meat processing plant on Sunday later showing signs of torture. Hundreds of Sunni residents from the area later demonstrated near the factory carrying banners that read "Get police troops out of our area."

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