BAGHDAD, Iraq - A wave of car bombings shook the Iraqi capital today, killing at least nine people as rebels stepped up their offensive to block the Jan. 30 national election. Other attacks were reported north and south of the capital, but the U.N. election chief said only a sustained onslaught could stop the ballot.

U.S. military officials put the death toll from the day's violence at 26, based on initial field reports. Iraqi authorities said 10 people were killed - one in a drive-by shooting on a political party office and the others in the bombings. The discrepancy could not be immediately resolved.

The violence began about 7 a.m., when a bomb packed into a truck exploded outside the Australian Embassy in Baghdad, killing two people. Two Australian soldiers were injured.

A half hour later, another car bomb killed six at a police station next to a hospital in eastern Baghdad.

A third car bombing struck at the main gate to an Iraqi military garrison at a disused airport in central Baghdad. The U.S. military said two Iraqi army soldiers and two Iraqi civilians were killed in that attack.

The U.S. military also said a car bomb detonated southwest of Baghdad International Airport, killing two Iraqi security guards.

Hours later, another car bomb went off in northern Baghdad around noon near a bank and a Shiite Muslim mosque. Police said one person was killed and one killed at that bombing.

Elsewhere in the capital, insurgents in a car fired on a Baghdad office of the Patriotic Union of Kurdistan, killing one of its members and wounding another, PUK officials said.

Fresh clashes erupted today between U.S. troops and insurgents in the northern city of Mosul. A car bomb exploded beside a U.S. convoy in the eastern part of the city, and two Iraqis were killed when American troops opened fire after the blast, witnesses said. There were no reported casualties among the Americans.

U.S. and Iraqi officials had predicted a steady increase in violence in the run-up to the election, in which Iraqi voters will choose a National Assembly and provincial legislatures. Sunni Muslim insurgents have vowed to disrupt the ballot.

Carlos Valenzuela, the chief U.N. election adviser in Iraq, said the intimidation of electoral workers by guerrillas seeking to derail this month's balloting is "high and very serious."

But Valenzuela told reporters Tuesday that only a sustained onslaught by insurgents or the mass resignation of electoral workers will prevent this month's national elections from going ahead.

U.S. troops have stepped up raids across the country, arresting scores of suspected insurgents in hopes of aborting plans to disrupt the ballot.

Today, the U.S. military acknowledged that its soldiers opened fire on a car as it approached their checkpoint, killing two civilians in the vehicle's front seat. Six children riding in the backseat were unhurt.