Two suicide bombers strapped with explosives blew themselves up on Sunday in the offices of two Kurdish parties aligned with US occupation forces in northern Iraq, killing at least 56 people and wounding 200.
About 20 people were killed in explosions at an arms depot in southern Iraq.
"They wanted to loot and steal ammunition from the bunker," Lieutenant-Colonel Robert Strzelecki said, adding that no coalition soldiers were hurt in the blasts south-west of Kerbala.
In the town of Balad, north of Baghdad, guerrillas fired rockets at a US supply base on Sunday, killing one US soldier and wounding 12, the US military said. Twelve Iraqi men and four women were arrested after the attack.
The Arbil offices of Iraq's two main Kurdish political groups were crowded with senior officials celebrating Eidul Azha when the bombers struck, killing many top leaders of the two groups.
Body parts were strewn among the debris and pools of blood congealed on the floor beside shards of shattered glass.
Those killed included Sami Abdul-Rahman, deputy prime minister of the KDP government in one half of northern Iraq. Akram Mantik, governor of Arbil province, his deputy Mehdi Khoshnau and the chief of the KDP headquarters. The top PUK official in Arbil was critically wounded.
The attack risks heightening ethnic tensions, complicating US plans to hand back sovereignty to Iraqis by end-June.
Wounded people filled the city's hospitals, which were in chaos, over-stretched with many doctors at home for the holiday. Staff was called back to help, and US helicopters brought medical assistance. Bodies were laid out in the corridors, with weeping relatives trying to identify the corpses.
Iraqi Foreign Minister Hoshiyar Zebari, a Kurd, blamed the attacks on the al-Qaeda network or its allies.
"It was an attack by terrorists, al-Qaeda and Ansar al-Islam," he said. Several senior Kurdish officials have been targeted in assassination attempts in recent years, attacks they blamed on the Ansar al-Islam group.
The co-ordinated attacks on the offices of the Kurdistan Democratic Party (KDP) and the Patriotic Union of Kurdistan (PUK) were the second-deadliest in Iraq since Saddam Hussein was toppled and marked the first time a major suicide assault involved attackers on foot rather than driving vehicles.
TOLL EXPECTED TO RISE: A senior US military commander said 56 people were killed and 200 wounded. Kurdish officials said the toll would rise.
Officials said security might have been too lax on the Feast of Sacrifice.
"Those who carried out the attacks were trained, experienced and had planned for the operation," said Sadiiq Ziwati, a KDP official in Mosul. "They knew that because of our ethics, we wouldn't be searching everyone who came to wish us a happy Eid."
Peter Galbraith, a former US diplomat and expert on the Kurds who was in Arbil, said the attack could strengthen the hand of Kurdish groups that want to break away from the rest of the country, threatening further chaos in Iraq.
"It is too early to predict the fallout, but the bombings will strengthen those in the Kurdish movement who want to insulate Kurdistan physically and politically from the rest of Iraq," Galbraith said.
"The significance of this is devastating to the leadership of the Kurdish Democratic Party, one of the US's biggest allies in the war," Galbraith said.
WOLFOWITZ: "WE ARE WINNING" US Deputy Defence Secretary Paul Wolfowitz, on a visit to Baghdad, said people like the Arbil attackers would be defeated.
"They're...not about Islam, they're not about Muslims, they're about their own fanatical view of the world and they will kill to try to advance it," he told reporters. "But we are winning and they are losing."
Wolfowitz also defended the decision to invade Iraq, despite mounting evidence intelligence that Saddam possessed an arsenal of weapons of mass destruction was faulty.
On Sunday, the White House and key congressional leaders negotiated details of an independent commission to investigate intelligence failures before the Iraq war.
President George W. Bush had earlier rejected an independent probe amid White House fears of a political witch-hunt by Democrats hoping to unseat him in this year's presidential election, but began in recent days to reconsider the position given the bipartisan pressure for an investigation.
Since the start of the war to oust Saddam, 366 US soldiers have been killed in action.