Ukrainian soldiers fired into the air Monday to disperse hundreds of Iraqis who rioted for jobs and food as a second southern Shiite Muslim (search) city was rocked by unrest — a barometer of rising frustration with the U.S. led-occupation in a region of Iraq considered friendly to the Americans.

Also Monday, a roadside bomb in the capital killed one American soldier and wounded two, bringing the U.S. death toll in the Iraqi conflict to 495. Large explosions rocked central Baghdad later in the day, but officials reported no casualties.

Trouble started in Kut, 95 miles southeast of Baghdad, when about 400 protesters marched for a third straight day on a government building to demand jobs. Someone in the crowd threw a grenade at police and Ukrainian soldiers guarding the building, injuring four Iraqi policemen and one Ukrainian, according to Lt. Zafer Wedad.

The Ukrainians then fired in the air to disperse the crowd, injuring one protester, Wedad said. He said the demonstrators hurled bricks at the building and trashed a post office in the city.

In a similar protest in Amarah on Sunday, waves of protesters rushed British troops guarding the city hall before being pushed back. On Saturday, clashes in Amarah killed six protesters and wounded at least 11.

Unrest in the Shiite areas has spread as the country's leading Shiite cleric, Grand Ayatollah Ali al-Husseini al-Sistani (search), has spoken out against the U.S.-backed formula for transferring power to the Iraqis.

In a full-page newspaper advertisement Monday, al-Sistani repeated his demand that a proposed provisional legislature be elected rather than chosen by regional committees as called for under a plan endorsed by the U.S.-led coalition and the Iraqi Governing Council.

Al-Sistani is highly influential among Iraq's majority Shiites.

No details were available about the death in Baghdad of the 1st Armored Division soldier. Most of the U.S. deaths in Iraq have occurred since President Bush declared an end to major combat on May 1.

Still, U.S. officials said Monday that insurgent attacks against coalition forces declined to an average of 17 a day in the past week, compared to 30 a day before Saddam Hussein was captured on Dec. 13. Most of the attacks are believed carried out by supporters of the ousted regime.

In the late Monday blasts, Iraqi and U.S. security officials said at least two mortars exploded near the Baghdad Hotel in the center of the capital. At least one round exploded in the Tigris River and the other exploded on the river bank, U.S. troops said. There were no casualties, the Americans said.

Also Monday, another roadside bomb exploded near an Army convoy in Ramadi, a town west of Baghdad, but the military said no U.S. casualties were reported. Residents said two Iraqis were killed when the Americans opened fire after the attack.

On Friday, U.S. soldiers uncovered a "large weapons cache" with the help of an Iraqi in Ramadi, the U.S. military said in a statement Monday.

It said the Iraqi led the troops to a house, where they found dozens of rocket-propelled grenades and a handful of launchers, nearly 220 pounds of explosives, 16 remote controlled homemade bombs and two surface-to-air missiles, the military said in a statement.

Also acting on an Iraqi tip, U.S. soldiers shot dead seven of the estimated 40 members of an armed gang allegedly trying to steal oil from a pipeline south of Samarra, 60 miles north of Baghdad, the Army said Monday.

Meanwhile, the Danish army said Monday that results of a new series of tests to determine whether 36 shells buried in the southern Iraqi desert contain a liquid blister agent could be expected by the end of the week. The shells, thought to be left over from the 1980-88 Iran-Iraq war, were uncovered last week.

Separately, the top U.S. administrator, L. Paul Bremer (search), said the United States is opposed to the maintenance of armed militias by Iraqi political parties. Groups vying to fill the country's power vacuum will have to lay down arms in a future democracy, he said.

"In a unified Iraq there is no place for political parties having armed groups," Bremer told reporters.