BAGHDAD: About 4,000 American ground troops supported by surveillance aircraft, attack helicopters and spy satellites swept towns and farmland south of Baghdad on Sunday searching for three American soldiers who disappeared Saturday after their patrol was ambushed, military officials said.

The Islamic State of Iraq, an insurgent umbrella group, claimed responsibility Sunday for the attack, which killed four American soldiers and an Iraqi Army soldier, and said it had captured the three missing Americans. The group offered no proof for its claim.

Elsewhere in Iraq, at least 55 people were killed and 155 wounded in two vehicle bombings, one against the offices of a leading Kurdish political party in a contested region of northern Iraq and the other in a market in Shiite-dominated eastern Baghdad, Iraqi officials said.

The ambush of the Americans on Saturday morning occurred near Mahmudiya, a farming town south of the capital that has been a battleground between Sunni Arab insurgents, Shiite militias and Iraqi and American security forces.

Lieutenant Colonel Christopher Garver, a U.S. military spokesman in Baghdad, said Sunday that three of the American soldiers killed in the attack had been identified but that "we're still going through the process of identifying" the fourth, suggesting that the soldier had been seriously disfigured

 

 

American officials said the soldiers had been traveling in two vehicles, which burst into flames during the ambush.

The attack, and the disappearance of the soldiers, comes at a critical time in the American engagement in Iraq. President George W. Bush has ordered about 30,000 fresh American troops to Iraq and has insisted that, given enough time and persistent American involvement, the country can be pacified. But the increase in American troops comes as public and congressional support for U.S. involvement in Iraq has waned.

American military officials said they were sparing no resources in their search for the missing soldiers.

"Everybody is fully engaged. The commanders are intimately focused on this," Major General William Caldwell said at a news conference with reporters from the Iraqi media, according to The Associated Press. He said the searchers were using "every asset we have, from national assets to tactical assets."

Two American soldiers were kidnapped last June after their unit was ambushed near Mahmudiya. Their bodies were found days later, mutilated and booby-trapped.

The Islamic State of Iraq, which includes Al Qaeda in Mesopotamia, posted its claims of responsibility on jihadist Web sites. "Clashes between your brothers in the Islamic State of Iraq and a crusaders' patrol in Mahmudiya, southern Baghdad province, has led to the killing and arresting of several of them," their message said.

The suicide attack in northern Iraq killed at least 50 people and wounded at least 115, said Brigadier General Mohammed al-Wagaa, an Iraqi Army commander in Mosul. It occurred just south of the border of the autonomous region of Kurdistan, in the town of Makhmur, which has a sizable Kurdish population.

In the attack, a man drove his explosives-laden car into the main gate of a compound that includes the offices of the Makhmur mayor and the Kurdistan Democratic Party, the organization led by Massoud Barzani, the president of Kurdistan.

It was the second vehicle bombing in five days against Kurdish targets in northern Iraq, suggesting the beginning of a terrorist offensive against the Kurdish authorities.

The blast destroyed several buildings and houses, "many cars" and a gas station, said Abdulrahman Belaf, the mayor of Makhmur, who was in his office at the time and was wounded in the attack. The town's police chief died in the blast, officials said.

Makhmur falls within a region that the Kurdish authorities want to annex as part of an expanded Kurdistan. The Constitution calls for a referendum before the end of year on whether a swath of territory in three northern Iraqi provinces, including the oil capital of Kirkuk, should become part of Kurdistan.

American and Iraqi officials say they expect a sharp rise in violence as the referendum nears, mainly led by Sunni Arab insurgents opposed to the expansion of Kurdistan's borders.

Kurdish officials said Sunday that they did not yet know who was responsible for the attack in Makhmur or whether it was related to an attack last week in Erbil, the capital of Kurdistan, in which a truck loaded with explosives detonated in front of offices of the Kurdish regional government, killing at least 19 people and wounding more than 70.

The Makhmur bombing was the deadliest attack of the day in Iraq on Sunday.

In Baghdad, a car bomb exploded at the Sadriya market in a predominantly Shiite quarter of eastern Baghdad, killing at least 5 people and wounding 40, an official at the Interior Ministry said.