Two trucks packed with explosives blew up Wednesday outside a Polish-run base south of Baghdad after coalition forces opened fire on the homicide bombers racing toward them. Eight Iraqi civilians were killed and at least 65 people were wounded, many of them coalition soldiers.

The two drivers also were killed, according to the U.S. military, but no information about their identities was available.

The Polish commander of the region, Gen. Mieczyslaw Bieniek, called the bombings near the base in Hillah, 60 miles south of Baghdad, a "well-coordinated attack." They came a week after two homicide car bombings killed more than 100 people.

U.S. officials have predicted an increase in attacks as the June 30 date for the transfer of sovereignty to Iraq approaches. Some insurgents fear their campaign could lose steam once power is returned to Iraqis, U.S. officials believe. However, major differences remain on how to choose a new government.

"The enemy's strategy is fairly clear," coalition military commander Lt. Gen. Ricardo Sanchez (search) told reporters Wednesday in Tikrit. "They plan to isolate us from the Iraqi people."

The bombing happened after 7:15 a.m. when two trucks loaded with explosives approached the front of the coalition base known as Camp Charlie. Guards fired at the vehicles, causing one to explode, said Lt. Col. Robert Strzelecki. The other struck a concrete barrier and exploded.

Eleven homes near the base collapsed in the blast and others were damaged, entire sides blown off. Debris littered the area.

Mohyee Mokheef, a 50-year-old cafe owner, who lives near the camp, said he was having breakfast with his family when he heard a faint first explosion and a second, louder one that shattered the windows in his home.

"I went out and walked toward the base, and I saw about eight damaged houses," he told The Associated Press. "I saw dead and injured Iraqis lying on the ground."

Men, women and children were among the dead. The wounded included at least 32 Iraqis, 12 Filipinos, 10 Poles and 10 Hungarians, officials said. One American soldier was hurt. The wounded Poles and Hungarians were all coalition soldiers; the wounded Filipinos included seven soldiers, two police officers and three civilian health workers.

Poland leads a multinational force of about 9,500 soldiers in south-central Iraq, and its troops also fought in the U.S.-led war to oust Saddam Hussein. A Polish officer was killed in Iraq last November, the first Polish soldier killed in combat since the aftermath of World War II.

Nearly 300 people have been killed in homicide bombings across Iraq since the beginning of the year, including about 100 people killed in homicide bombings at a police station in Iskandariyah, south of Baghdad, on Feb. 10 and an army recruiting center in the capital on Feb. 11.

Those attacks have fueled speculation that Islamic extremists, possibly linked to Al Qaeda, were playing a greater role in the anti-coalition insurgency, which U.S. military officials believed had been spearheaded by loyalists of Saddam Hussein.

"I suspect that Ansar-Islam and Al Qaeda were behind these operations because they want to create strife between Sunnis and Shiites and between the Shiites and Americans," Mokheef said. "They want to derail the elections process."

The violence also came as members of the U.S.-appointed Governing Council distanced themselves further from the U.S. idea of holding regional caucuses to elect an interim government after the planned June 30 handover of power.

In Baghdad, Mouwafak al-Rubaie, a Shiite Arab member of the Governing Council, said Wednesday that the idea of using caucuses was "gone with the wind," adding that the only solution palatable to Iraqis are general elections, as demanded by Shiite clerics.

"Anything else will make things worse and the results will be damaging to Iraq," he said. "Only elections will give the legitimacy needed for any future political process or body."

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 about how to choose the interim government. The world body is expected to give a report this week.

On Tuesday, the United States also unveiled a list of 32 wanted people, including suspected cell leaders, former members of Saddam's military and regional Baath leaders thought to be helping the insurgency.

At least seven of the names were former colonels or other high-ranking officers in Saddam's military who held important posts in the Baath party.

Atop the list, with a $1 million reward, is Mohammed Yunis al-Ahmad, a former top Baath Party (search) official. Rewards between $50,000 and $200,000 were offered for the others.

Until now, U.S. officials have not made public a list of suspected leaders of the insurgency that erupted after the regime's collapse and has killed more American soldiers than did the invasion that toppled Saddam. The violence has persisted despite the Iraqi leader's capture in December.

Also Wednesday, army investigators in Tikrit said they will examine why a mortar round from an army base smashed into a neighborhood home, killing three Iraqis, including a 10-year-old child. Lt. Col. Steven Russell said it was possible that the mortar crew was given the wrong coordinates when it fired the 120mm round Tuesday from the base that sits on the banks of the River Tigris near Saddam's hometown. "There is no wrongdoing at all suspected on the part of the firing crew," he said late Tuesday.