U.S. forces broadened their hunt Saturday for three missing comrades beyond the rural area south of Baghdad where they disappeared, and their top commander expressed optimism that at least two of them were still alive a week after their isolated outpost was ambushed.

At least one soldier was killed Saturday and another seriously wounded as insurgents attacked the searchers with guns, mortars and bombs. The military reported a dozen other U.S. troop deaths in Iraq since Thursday.

Northeast of the capital, there was more gruesome Iraqi-on-Iraqi murder. Men in Iraqi army uniforms rousted Kurdish villagers from their homes, separated out the able-bodied men, and shot dead 15, according to an Iraqi general and a Kurdish political party.

It was the latest incident in months of sectarian killings in lawless Diyala province and officials said Saturday that the local army commander was fired by the government.

Violence also marred the last visit to Iraq by British Prime Minister Tony Blair before he leaves office. A mortar round hit the British Embassy compound and two more elsewhere in the Green Zone while Blair was in Baghdad. And then, although Blair's itinerary was not announced, explosions also were heard when Blair went to Basra in southern Iraq, where British forces are based.

The search for the missing soldiers involves some 4,000 troops who "will not stop searching until we find our soldiers," said Lt. Col. Christopher Garver, a U.S. military spokesman in Baghdad. "We're using all available assets and continuing to assault the Al Qaeda in Iraq network," he said.

Acting on a tip, Garver said troops raided a building in Amiriyah on Saturday morning and captured nine Iraqis suspected of involvement in the attack. Amiriyah is a stronghold of Sunni insurgents with close tribal ties to Quarghuli, where the outpost was overrun.

He said U.S. troops also detained two Iraqis in Baqouba who he said were "associated" with the Al Qaeda command network. He did not tie those arrests directly to the missing soldiers. Their outpost in Quarghuli is about 12 miles south of Baghdad and about 50 miles from Baqouba, a violence-wracked city to the north.

A group that claims ties to Al Qaeda has claimed responsibility for the May 12 attack that resulted in the kidnapping and the deaths of four American soldiers and an Iraqi aide. However, there has been no evidence, such as photos, video or audio, released by that or other groups.

Army Gen. David Petraeus, the senior American commander in Iraq, told the Army Times newspaper in an interview Friday night that U.S. forces were focusing on an insurgent who is "sort of an affiliate of Al Qaeda."

He said an informant provided U.S. forces with names of those who took part in the raid and kidnapping but they were still at large. "We've had all kinds of tips down there. We just tragically haven't found the individuals," he said.

Petraeus said he did not know whether the three missing soldiers, from the Army's 10th Mountain Division, were alive. But "as of this morning, we thought there were at least two that were probably still alive," he said.

"At one point in time there was a sense that one of them might have died, but again, we just don't know."

An Iraqi army intelligence officer, who said he helped interrogate two suspects detained in recent days in Mahmoudiya, said they confessed to participating in the raid. Mahmoudiya is the largest town in the search area.

They said 13 insurgents conducted the surprise attack and then escaped in two groups. The leader of the group, along with some gunmen, took the kidnapped soldiers to a destination unknown by the two detainees, he said.

He added that the two detainees gave interrogators the hiding place for weapons used in the ambush and U.S. troops went there and took them.

In the week since the attack in Quarghuli, some two dozen U.S. troops have been killed in Iraq. Five were announced on Saturday, four of which occurred on Friday.

Those numbers were far eclipsed the toll of Iraqis on Saturday alone.

The execution-style slayings of 15 Kurds in Hamid Shifi, 60 miles northeast of Baghdad by the men posing as troops, stood out because details of the event were known.

By contrast, there were no narratives attached to the 20 bodies found Saturday around Baghdad. Police said they were all men, handcuffed, blindfolded, shot and then dumped on the streets. All but three were found on the Sunni Muslim side of city.

In all, at least 93 people were killed or found dead Saturday nationwide.

One well-known Iraqi politician close to the Bush administration narrowly escaped injury.

Ahmad Chalabi was hustled to safety by his bodyguards when attackers struck with mortars and firearms in Buhriz, about 40 miles north of Baghdad and just south of Baqouba.

Chalabi, who helped President Bush sell the 2003 invasion of Iraq to the American public, told Iraqi television afterward that was helping to mobilize the tribes of Diyala province against insurgents but they needed more help from the U.S.-led military forces.

"The multinational forces should be more active and support the residents and the Iraqi forces to counter the terrorism," he said.

Meanwhile, the health of one of Iraq's most powerful Shiite leaders, Abdul-Aziz al-Hakim, was at risk from cancer.

Aides to al-Hakim said he was flown to Houston, Texas, on Wednesday for tests after doctors in Baghdad suspected he had lung cancer. He had complained of a cough and had high blood pressure, said members of his staff who spoke on condition of anonymity.