Insurgents targeted Iraqi police and Shias in a string of bombings, adding to sectarian tensions as US authorities pressure Iraqi politicians to quickly reach a deal on forming a government of national unity.

Three aid workers from the Christian Peacemaker Teams -- Canadians Harmeet Sooden, 32, and Jim Loney, 41, and Briton Norman Kember, 74 -- were rescued in western Baghdad, US Colonel John Snow told AFP.

Their US colleague Tom Fox, seized with them on November 26, was slain two weeks ago and his body found dumped in the city.

"The three hostages Norman Kember, a British hostage, (and) two Canadian hostages, have been released as a result of a multi-national force operation which took place earlier today," British Foreign Secretary Jack Straw said in London.

"British forces were involved in this operation. It follows weeks and weeks of very careful work by our military and coalition personnel in Iraq and many civilians as well," Straw added.

"I am delighted we now have a happy ending to this ordeal."

Their abduction was claimed by a group calling itself the Brigades of the Swords of Righteousness, which threatened to kill them unless all Iraqi prisoners were released.

Straw said Kember was in a "reasonable condition" and recovering in Baghdad's top-security Green zone where the British and US embassies and the Iraqi government are based. But he said the two Canadians needed hospital treatment.

Straw said he had talked with Kember's wife Pat throughout her husband's ordeal and had spoken to her again since his release. "It goes without saying that she is absolutely delighted, elated with this news," he said.

A Downing Street spokesman said Prime Minister Tony Blair "is delighted by the news. He is particularly pleased for those released and their families."

The three freed hostages last appeared in a video broadcast on pan-Arab satellite television Al-Jazeera on March 7 in which they issued a new appeal for their governments to work for their release.

Fox was found handcuffed and shot dead on a rubbish dump in west Baghdad on March 9. His body had been wrapped in a blanket and stuffed in a plastic bag.

At least 430 foreigners are known to have been taken hostage in Iraq since the March 2003 US-led invasion, a US diplomat said in Baghdad earlier this month.

They include 41 US nationals, some of them Iraqi-Americans.

Seven are still being held, including US journalist Jill Caroll, a 28-year-old freelance journalist who was on assignment for the Christian Science Monitor when she was abducted on January 7.

She has since appeared in three videos broadcast on Arab television. The latest deadline set by her captors passed in late February with no word on her fate.

Earlier this week, a German television station said that the government in Berlin believed that two German engineers kidnapped in Iraq in January were still alive and were being held for criminal not political purposes.

Rene Braeunlich and Thomas Nitzschke were seized in northern Iraq on January 24 and their captors have issued two videos in which they threatened to execute the men unless Germany closes its embassy in Baghdad and ends cooperation with the Iraq government.

Another Briton, Ken Bigley, was beheaded in October 2004 by a group led by Abu Musab al-Zarqawi, the Jordanian-born leader of Al-Qaeda in Iraq and the country's most wanted man with a 25-million dollar US bounty on his head.

And Margaret Hassan, a British-Iraqi aid worker who was kidnapped in 2004 is also believed dead though her body was never found.

56 KILLED IN VIOLENCE
AP from Baghdad reports: At least 56 Iraqis died yesterday in violence, including a car bombing that killed 25 people in the third major attack on a police lockup in three days.

A suicide car bomber detonated his explosives at the entrance to the Interior Ministry Major Crimes unit in Baghdad's central Karradah district, killing 10 civilians and 15 policemen employed there, authorities said.

The Interior Ministry is a predominantly Shiite organization and heavily infiltrated by members of various Shiite militias. The unit targeted Thursday investigates large-scale crimes and has about 20 suspected insurgents in custody, police Lt Col Falah al-Mohammadawi said.

He ruled out that the assault was aimed at releasing the prisoners -- the goal of previous days' attacks on other police facilities.

Insurgents engineered a successful jailbreak that released more than 30 prisoners north of Baghdad on Tuesday. On Wednesday, the militants laid siege to a prison south of the capital, but US troops and a special Iraqi unit thwarted the pre-dawn attack, capturing 50 of the gunmen, police said.

In yet another attempt to free prisoners, gunmen on Thursday attacked Iraqi soldiers escorting detainees to a courthouse in northern Baghdad, and one of the captives was killed in the crossfire before authorities arrested eight of the militants, police said.

In the assault on the crime unit, more than 35 people, mainly employees at the crimes unit, were wounded, police said.

A second car bomb hit a market area outside a Shiite Muslim mosque in the mixed Shia-Sunni neighborhood of Shurta in southwest Baghdad. At least six people were killed and more than 20 wounded, many of them children, police said.

Roadside bombs targeting police patrols killed four others -- two policemen and two bystanders -- in Baghdad and at least one policeman in Iskandariyah, 30 miles south of Baghdad. Dozens were wounded, police said.

Another two policemen were killed and two were wounded when gunmen ambushed a convoy in north Baghdad, an attack that police said was an aborted attempt to free detainees being transferred north to Mosul.

Also in Baghdad, two police were killed in gunbattles with insurgents. Two civilians -- a private contractor and a power plant employee -- were slain in drive-by shootings.

A mortar round fell on a Baghdad house, wounding three civilians, said police Lt Ziad Hassan. Another civilian was seriously wounded by an Iraqi army patrol that was shooting in the air to clear traffic in a western neighborhood, police said.

Fourteen more bodies were found in an ongoing series of shadowy sectarian killings: six in the capital and eight brought in by US forces to a hospital in Fallujah, 40 miles west of Baghdad, police said.