Data compiled by the UN shows that an average of 100 civilians were killed each day during May and June. More than 60 were killed in car bombs in Baghdad and Kirkuk on Sunday.

Mr Maliki has already announced a clampdown on Baghdad, with additional checkpoints and troops to maintain a curfew. Yesterday he said it was time to move to the next stage and that the new security plan would involve the Iraqi army taking control of the neighbourhoods on the edge of Baghdad to stop insurgents using them as bases. He listed the neighbourhoods and said locals who had fled the violence would be encouraged to return and that Iraqi forces would be stationed there.

The US military revealed at the weekend that it is planning to send extra troops into Baghdad as part of this second phase.

The US and Iraq military know they have to establish control of Baghdad before they can attempt doing so with the rest of the country. Iraqi forces took over one of the country's 18 provinces this month but the prime minister refused to speculate on when the army will be in a position to replace the US and other international forces in the remaining 17.

Mr Maliki, who is scheduled to meet George Bush in Washington today, vehemently denied the country was heading towards civil war and eventual break-up.

Asked why the former dictator Saddam Hussein, who is on hunger strike, was not allowed to die, Mr Maliki said: "Because we want to put him on trial for the huge crimes he committed and to show the world the extent of his crimes."

Saddam was due in court yesterday but was taken to hospital at the weekend because of a deterioration in his condition. He was being fed through a tube after psychological counselling.

In Afghanistan, meanwhile, the British army will be provided with stronger armoured vehicles to withstand attacks from rocket-propelled grenades and roadside bombs, the defence secretary, Des Browne, said yesterday.

The vulnerability of existing vehicles, notably Land Rovers in which several British soldiers have died in southern Iraq, led commanders urgently to demand tougher equipment.

In a programme starting at the end of the year, the army will be provided with more than 300 new armoured vehicles, mainly German-designed Pinzgauers and US Cougars.

On Tuesday, two roadside bombs exploded in the city, killing two civilians and wounding two bystanders and a policeman.

In another attack, a family of Shiite civilians who had been threatened by a sectarian death squad were ambushed by gunmen as they fled a mainly Sunni neighbourhood south of the city, medical and defence officials said.

Two of the family were killed and one was wounded when their removal van was sprayed with bullets.

Four other civilians were shot dead around the capital, two of them in drive-by shootings, while the corpses of two tortured murder victims were also found by the roadside, police said.

Iraq's embattled Prime Minister Nuri al-Maliki was due in Washington on Tuesday to discuss the situation with his main ally and talk up his government's plan to take full responsibility for security.

The Pentagon has confirmed that it is to redeploy US forces in Baghdad from outside the capital in a bid to halt the spiralling violence.

Last month, in a plan designed finally to ensure security in the capital, more than 50,000 troops were deployed in the city. The killing has shown no sign of easing.

US officials said the extra troops would be sent from other areas of Iraq.

An average of more than 100 civilians per day were killed in violence in Iraq in May and June, according to a report by the UN Assistance Mission in Iraq.

White House spokesman Tony Snow admitted that a plan brought in six weeks ago to improve security in the Iraqi capital "has not achieved its objectives".

"It's pretty clear that there's an attempt in Baghdad to create as much chaos and havoc as possible," he said, quoted by AP news agency.

"And it's important to make sure that we address this."

When the two leaders met in Baghdad last month, President Bush offered support to a newly-formed government which had just been boosted by the killing of the insurgent leader Abu Musab al-Zarqawi.

The mood then was unusually positive, reports the BBC's James Coomarasamy in Washington - but this latest meeting comes on the back of a failed security operation in Baghdad.

Mr Maliki has also pledged to convey his concerns to Washington about Israel's actions in Lebanon, arguing that images of suffering Lebanese civilians are a powerful recruiting tool for extremists.

Struggling security

Baghdad's current security plans, brought by the Iraqi government six weeks ago, have seen thousands of extra Iraqi troops on the streets, backed by US forces.

Extra checkpoints have been set up to search vehicles in many parts of the city, overnight curfews have been extended and raids conducted on suspected insurgent hideouts.

But a huge blast in the suburb of Sadr City early this month, forced the government to review its plan.

Some 66 people were killed and more than 100 others injured in the attack, prompting an emergency meeting of the cabinet's security committee.

Other attacks have been carried out every day in different parts of the city, including bombings, abductions and sectarian killings.

Last Friday, authorities extended a curfew banning traffic in the capital during Friday prayers in an attempt to stem the violence.

Mr Maliki's meeting with President Bush comes after a visit to London on Monday where he held talks with British Prime Minister Tony Blair.