Updated

Homicide bombers detonated explosives outside a Polish-run base Wednesday, killing 10 Iraqis and wounding more than 100 people, more than half of them coalition soldiers. The United States arrested seven guerrillas believed linked to Al Qaeda (search) in an early morning raid to the north.

The attack in Hillah, the third homicide bombing of security targets in two weeks, was part of a wider effort "to isolate us from the Iraqi people," coalition military commander Lt. Gen. Ricardo Sanchez told reporters in Tikrit (search).

Coalition and military officials said at least 106 people were hurt in the blasts, which happened in the Hayy Babil neighborhood near Camp Charlie. The wounded included 32 Iraqis and 26 Poles, as well as Hungarians, Bulgarians, Filipinos and an American.

The casualty toll could have been much higher had guards not opened fire and prevented the bombers from entering the camp. One truck exploded under the gunfire and another blew up after hitting a concrete barrier.

The 7:15 a.m. blasts -- from 1,540 pounds of explosives -- flattened 11 homes nearby and blew down the entire sides of several other houses in this town south of Baghdad (search).

The stepped-up violence could be aimed at preventing U.S. administrators from handing over power to the Iraqis on June 30, when Iraqi security forces would also take a more prominent role against the insurgency.

A senior U.S. official said Wednesday the Bush administration is considering a major shift in its plan for transition to Iraqi self-rule, possibly extending and expanding the Governing Council so it can take temporary control of the country on July 1.

The administration is eager to see if U.N. Secretary-General Kofi Annan approves of the idea of a major shift, the Washington official told The Associated Press on condition of anonymity.

On Wednesday, members of Iraq's Governing Council distanced themselves further from the U.S. idea of holding regional caucuses to elect an interim government after the planned hand over.

Mouwafak al-Rubaie, a Shiite Arab member of the Governing Council, said the idea of using caucuses to choose a provisional legislature was "gone with the wind." He said the only solution palatable to Iraqis is general elections.

U.S. Secretary of State Colin Powell said Tuesday that the United States was committed to giving the Iraqi people control of their country by July 1 but remained open to ideas from the United Nations. The world body sent a team to Iraq to evaluate the best way forward and is expected to report this week.

Governing Council member Dara Nor al-Din, a Sunni Kurd, said the Iraqi body was waiting "for the decisions reached by the United Nations on whether the elections are possible and what ideas they have to solve the problem."

Annan is expected to support the Bush administration and advise against direct elections for an interim government in Iraq, another U.S. official in Washington said on condition of anonymity.

Annan on Thursday is to receive a firsthand report at the United Nations from Lakhdar Brahimi, his special adviser who led the U.N. team to Iraq to assess election possibilities and possible changes that might be acceptable to a wide range of Iraqi leaders.

Earlier Wednesday, U.S. troops arrested seven militants believed linked to Al Qaeda in the turbulent city of Baqouba, north of the capital, the military said. It gave no details on the nationalities of the militants. There was no indication the attacks and the U.S. raid were directly linked.

Troops from the 4th Infantry Division carried out the raid early Wednesday targeting an "anti-coalition cell" that may have ties to Usama bin Laden's terror group, a statement from the U.S. command said.

Homicide attacks have killed 300 people, mostly Iraqis, since the beginning of the year. They have fueled speculation that Islamic extremists, possibly linked to Al Qaeda, were playing a greater role in the anti-coalition insurgency. U.S. military officials had believed the attacks were spearheaded by Saddam Hussein loyalists.

Two homicide bombings killed more than 100 Iraqis last week. Polish Gen. Mieczyslaw Bieniek, commander of the 9,500-member Polish military contingent, said Wednesday's bombings, about 55 miles south of the capital, were a "well-coordinated terrorist attack."

Mohyee Mokheef, a 50-year-old cafe owner who lives in the neighborhood, said he was having breakfast when he heard a faint first explosion and a second, louder one that shattered the windows in his home. He blamed Al Qaeda and an Iraq-based group linked to it, Ansar al-Islam.

"I saw dead and injured Iraqis lying on the ground," he told The Associated Press. "I suspect that Ansar al-Islam and Al Qaeda were behind these operations because they want to create strife between Sunnis and Shiites and between the Shiites and Americans. They want to derail the elections process."

Most of the wounded among multinational troops were hurt by flying debris and glass. The injuries were not life-threatening.

Another debate connected to the hand-over of power is the drafting of an interim constitution and the role Islam will have in it.

The council's president, Mohsen Abdul-Hamid, appeared to back away from an earlier demand that the constitution specify that Islam is the principle basis for Iraq's laws. L. Paul Bremer, the top U.S. administrator in Iraq, suggested this week he would block such a move.

"This question has not reached its final stage," Abdul-Hamid, a Sunni Muslim, told reporters. He stressed that the draft interim charter says Islam is "a primary source" -- as opposed to the primary source -- for legislation.