BAGHDAD, Iraq (AP) – A suicide attacker detonated a massive car bomb yesterday outside the fortified enclave housing the Iraqi government’s headquarters and the US and British embassies, killing at least 10 and wounding 40.

Meanwhile, gunmen in northern Iraq assassinated a provincial governor.

The bombing was the worst attack in Baghdad since the United States handed power to an Iraqi interim government June 28. The violence sent a strong signal that Iraqi insurgents view the new government, which is just beginning to assert its authority, as an extension of the US occupation.

“This is a naked aggression against the Iraqi people,” Interim Prime Minister Iyad Allawi said as he toured the bombing scene. “We will bring these criminals to justice,” he said as he surveyed the scene.

Allawi said the bombing was retaliation for the government’s arrests of terror suspects.

As Iraqi officials vowed to crack down on the insurgents, the Philippines worked to withdraw its 51-member peacekeeping force, a move aimed at saving the life of Angelo dela Cruz, a Filipino truck driver held by militants.

The withdrawal was criticised by some as caving in to terrorists, but Filipino officials said now was not the time for debate.

“What is important now is the safety of Angelo,” Vice President Noli di Castro said in a statement.

Another militant group, headed by Jordanian militant Abu Musab al-Zarqawi, killed one of two Bulgarian truck drivers it was holding hostage, the Bulgarian government confirmed Wednesday. In a video shown on the pan-Arab television station Al-Jazeera early yesterday, the group, which had demanded the release of Iraqi detainees, said it would kill the second man in 24 hours.

The violence yesterday began about 9:15 am when a suicide bomber detonated a car packed with 450 kilograms (1,000 pounds) of explosives at a checkpoint just outside the so-called Green Zone, former home to the US occupation government and currently home to the Iraqi interim government and the US and British embassies.