Three US soldiers have been killed as Iraqi and US troops moved into Baghdad to tackle increasing sectarian violence in the capital.

The US military said on Wednesday: "Three soldiers assigned to 1st Brigade, 1st Armored Division died from enemy action while operating in Al-Anbar province today."

A US Blackhawk helicopter also crashed in Anbar, leaving two US soldiers missing and four injured.

Al-Anbar has been the scene of the fiercest attacks by anti-US fighters.

In the last few weeks 12,000 additional US soldiers have been re-deployed into Baghdad from north-western Iraq.

Five civilians died and 20 were hurt when a mortar shell exploded in a built-up district of Baquba, north of Baghdad.

The attack collapsed a three-storey building near to a Shia mosque, police said. Witnesses feared some people were still trapped in the rubble.

Police said a bomb targeting a US patrol in east Baghdad had killed one civilian and injured another, while in Basra an Iraqi army colonel was shot dead on his way to work, the army said.

Two separate roadside bombs in Kirkuk also killed one civilian, wounded another and hurt three Iraqi soldiers.

In July almost 2,000 bodies were brought to Baghdad's morgue, an official there said on Wednesday.

This is the highest number since early spring when a Shia shrine attack in the city of Samarra in February sparked a wave of sectarian bloodshed. The July toll of 1,815 was an increase from 1,595 in June.

Dr Abdul Razzaq al-Obaidi,the assistant manager of the Baghdad morgue, said that about 90% of the deaths were due to sectarian violence.

He said: "Most of the cases have gunshot wounds to the head. Some of them were strangled and others were beaten to death with clubs."

The rising daily death toll has put new pressure on the American military to restore law and order to Baghdad.

Major-general James Thurman, commander of US-led forces in the Baghdad region, said: "We must dramatically reduce the level of violence in Baghdad that is fuelling sectarianism.

"Iraqi and US forces will help the citizens of Baghdad by reducing the violence that has plagued this city since the Samarra bombing."

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