Blasts and attacks pockmark Iraq

Iraqis bear the brunt of the continuing violence

At least six Iraqis have been killed in a car bomb attack north of Baghdad - the latest in a string of attacks.

A statement purporting to be from a group led by suspected al-Qaeda operative Abu Musab al-Zarqawi claimed the "suicide" attack.

Dozens of people were hurt in the blast outside the gates of a US base at Taji, some 30km (20 miles) from Baghdad.

Two Americans and two Poles were killed on Saturday in an attack claimed by the same group.

At least 12 Iraqis and one Briton also died in separate attacks.

The attacks come despite a plea for an end to violence by the country's newly-appointed Prime Minister Iyad Allawi, who says foreign troops are needed "until Iraq is capable of handling its own security problems".

Bomb at base

The car bomb in Taji reportedly went off as Iraqi civilians lined up for work at the US military base.

Two US soldiers were reported to be among between 20 and 70 people injured in the bomb.

Ambulances, Humvees and police rushed to the base - which was once used by the Iraqi air force and now houses the US Army's First Cavalry Division.

In an statement whose authenticity could not be confirmed, a group led by al-Qaeda-linked operative Zarqawi said it carried out the attack.

"One of the heroes from this country, God rest his soul, targeted a camp for US forces in Taji, north of Baghdad, inflicting huge losses on them," said the statement.

The statement purported to be from the Tawhid wa al-Jihad Group, which also claimed responsibility for an attack on Saturday in which four foreigners died.

Contractors killed

Two Polish and two American contractors working for Blackwater security firm died when their convoy was ambushed as it travelled through Baghdad.

Their bodies were reportedly mutilated and burnt after the attack.

"The charred remains of four people were brought to a Baghdad morgue from the place of attack," Grzegorz Szczesniak, a foreign ministry official, told Reuters news agency.

The ministry said a third Pole was slightly injured. DNA samples of the victims have been sent to their home countries for identification.

Meanwhile, the UK Foreign Office said a Briton died when a car carrying civilian contractors was attacked in the northern city of Mosul on Saturday.

The mutilation of the bodies of four Blackwater contractors killed in Falluja on 31 March sparked a month-long siege of the city by the US in which hundreds died.

Police station assault

Saturday also saw an attack on a police station in the town of Musayyib, south of Baghdad.

It left at least 10 Iraqi police and two civilians dead.

Police officers said guerrillas disguised as policemen entered the building and forced policemen into a cell at gunpoint before planting explosives in the police station.

When locals tried to free the police, the explosives were detonated, witnesses said.