A prominent member of Iraq's National Assembly was killed Tuesday in a suicide car bombing, the second lawmaker to be assassinated since the assembly was elected five months ago.

Dhari Fayadh, a Shiite Muslim tribal leader who was the assembly's oldest member, was driving into Baghdad from his home on the outskirts of the capital when a car approached his motorcade and exploded, according to police. Fayadh's son and two bodyguards also died in the attack.

Assailants killed two American soldiers in separate suicide car bombings in northern Iraq, the U.S. military reported. Shortly before noon, a bomb exploded close to a U.S. military base near Balad, killing one soldier and wounding another. At about 4:15 p.m., an attacker detonated explosives near a combat patrol west of Tikrit, killing one soldier and wounding two.

U.S. and Iraqi forces, meanwhile, began another sweep aimed at driving insurgents out of western towns along the Euphrates River and disrupting the flow of fighters and supplies to Baghdad and other areas of Iraq.

Focusing on the area between the towns of Hit and Haditha, Operation Sword, like a handful of other such assaults in the past two months, involves about 1,000 U.S. Marines, soldiers and sailors and about 100 Iraqi troops.

Fayadh, believed to have been in his late eighties, was the leader of a prominent tribe from southern Iraq, the Albu Amer, and was first elected to an Iraqi legislature under the monarchy that was toppled nearly 50 years ago. He was elected to the current legislature as part of the Shiite slate that holds a majority of seats, and he served as assembly speaker at the opening session in March.

A statement posted on an Internet site purportedly from al Qaeda in Iraq, an insurgent group, asserted responsibility for Fayadh's killing.

"His death at the hands of terrorists is a great loss of a fine man and another reminder of the need to uproot terrorism," said Ridha Jawad Taqi, a spokesman for the Supreme Council for the Islamic Revolution in Iraq, a leading party in the ruling Shiite coalition.

The first assembly member to be slain was Lamia Abed Khadouri Sakri, who was gunned down on April 27 in eastern Baghdad. Like Fayadh, Sakri was a Shiite, though she was not a member of the ruling coalition.

Iraqi President Jalal Talabani, marking the first anniversary of the transfer of sovereignty from occupation authorities to appointed Iraqi leaders, said, "We congratulate the Iraqis and hope we'll defeat terrorists and Saddamist criminal gangs as soon as possible."

Talabani told reporters that until Iraq's security forces were capable of tackling the insurgency, the country needed foreign troops to protect it. "We are working to say farewell to these forces as soon as possible, but after we accomplish forming the Iraqi forces," he said.

In the city of Samawah, about 150 miles south of Baghdad, one person was killed when police fired on a crowd of protesters demanding jobs with the police force, the Reuters news agency reported. Four police officers and six civilians were injured in the clash, which was sparked when some of the protesters began throwing rocks.

"These are unemployed people and have the right to protest," Gov. Abu Ahmed Rumaithi of Muthana province, where Samawah is located, told al-Arabiya television. "There are some people who interfered and provoked them to violence. Our province is stable, and those who provoked the violence don't want it to be stable. I have formed a committee of police officers to investigate the incident, because we don't accept shooting people."

In Baghdad, American soldiers killed an Iraqi news executive when he did not pull over as a U.S. convoy passed on a road in Baghdad, according to Muhanad Jawad, a physician quoted by the Associated Press. Ahmed Wael Bakri, a program director at al-Sharqiya TV, was the third Iraqi journalist alleged killed by U.S. forces in similar incidents in the past week. The U.S. military said it was investigating.

On Sunday, Maha Ibrahim, a news editor with al-Iraqiya television in Baghdad, was killed in the capital when U.S. troops opened fire after apparently coming under attack, channel director Saad al-Bayati told the Associated Press.

On Friday, an Iraqi reporter working for an American news organization was shot and killed in Baghdad, allegedly by U.S. troops, after he apparently did not respond to a shouted signal from a military convoy, witnesses said.

Special correspondents Khalid Alsaffar and Omar Fekeiki contributed to this report.

Marine Lance Cpl. Cheston Bailon, right, of Shiprock, N.M., points his rifle at an Iraqi man in the town of Hit as troops enter his house to search it as part of Operation Sword, an anti-insurgent sweep involving about 1,000 U.S. troops.A relative mourns the killing of Dhari Fayadh, the oldest member of Iraq's National Assembly. His son and two bodyguards were also killed.