At least 65 Iraqis died today in the latest round of bomb attacks as the campaign of violence by militants showed no sign of relenting.

A suicide bomber blew himself up in a crowd of migrant Shia Muslim workers queuing for jobs in Saddam Hussein's hometown of Tikrit, killing at least 27 people and wounding 75.

"Some people had their heads torn off by the explosion, some were burned, some were ripped to pieces," said Ibrahim Mohammed, who was in the crowd.

Security has been high in Tikrit since a suicide bomber in a taxi killed eight people last Friday, but new rules forbidding anyone from driving alone in a car appear to have failed to prevent the latest attack.

The violence is largely being carried by rebels from the Sunni Muslim sect, who target Shias in an apparent attempt to provoke sectarian civil war.

Elsewhere, a suicide bomber walked up to an army recruitment centre in the town of Hawija in northern Iraq and detonated his belt of explosives, killing at least 32 people and wounding 34.

There were three car bomb attacks in Baghdad, killing three civilians and wounding nine near a police station in the southern suburb of Dora, and two policemen and a woman civilian in the Yarmouk district. Two people were wounded by a bomb near a bakery in New Baghdad.

The dreadful litany of violence brings the death toll to more than 400 in the days since Iraq finally formed a government. The rebels appear to be trying to derail the political process.

Insurgents are holding two hostages - Douglas Wood, an Australian engineer seized two weeks ago, and Akihiko Saito, a Japanese security contractor and former soldier who was snatched in Baghdad on Sunday by the ruthless Ansar al-Sunna group, which has murdered numerous captives.

Militants have also kidnapped Raja Nawaf, the governor of the restless province of Anbar, and are demanding in return the release of captured fighters loyal to Abu Musab al-Zarqawi, who heads the al-Qaeda network in Iraq.

The US army is carrying out an offensive on the Syrian border, near where Mr Nawaf was seized, in an attempt to destroy the strongholds of foreign fighters who enter Iraq to join the unrest. More than 1,000 troops are involved in Operation Matador, and claim to have killed at least 100 insurgents since the offensive began in villages along the Euphrates river on Saturday night.

Marine Lieutenant General James Conway, the director of operations for the US Joint Chiefs of Staff, said at the Pentagon that the assault had run into well-equipped and trained fighters, who had put up unexpectedly stern resistance.

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