Updated

Thousands of Shiite Muslims rallied Friday in the southern city of Basra to show support for Iraq's new constitution and the Shiite-dominated government. The U.S. military said three American soldiers were killed in action in Baghdad and south of the capital

Also Friday, five Iraqi soldiers were killed and nine wounded in a bombing targeting their convoy near Beiji, 150 miles north of Baghdad, the Iraqi military said.

The demonstration by at least 5,000 people in Basra, the country's second largest city, was organized by the Supreme Council of Islamic Revolution in Iraq and the Shiite Dawa Party. It was larger than the rallies Sunni Arabs have staged against the constitution recent weeks.

The two parties are the largest Shiite political groupings in Iraq, and their representatives played a key role in drafting the new charter, the subject of a referendum on Oct. 15.

Demonstrators chanted "Yes to the constitution" and carried banners that said: "The constitution is a guarantee for better future," and "Freedom and justice will be achieved by this constitution."

In Ramadi, a Sunni city west of Baghdad, several hundred people demonstrated against the constitution, chanting "We are brothers, Sunnis and Shiites. We will never sell this country."

Numerous demonstrations for and against the proposed charter have highlighted the deepening rift between the Shiite and Kurdish politicians who pushed the draft through parliament last weekend and the Sunni Arabs who oppose it. Sunni leaders have urged their community to vote against the constitution because its provision for a decentralized Iraq comprised of federal states would divide the country.

In continuing sectarian violence, unidentified gunmen opened fire on Sunni Muslim worshippers at Friday prayers in two mosques south of Baghdad, killing two people and injuring four, police said.

The first attack occurred when a lone gunman entered the Mizael Basha mosque near the town of Zubeir, 12 miles southwest of Basra, and sprayed automatic fire on worshippers during dawn prayers. One man was killed and four injured, police Col. Nouri al-Fayadh said.

Another Sunni mosque, the Rashidiya, was later attacked by a group of gunmen who fled after shooting dead a guard, police said.

In Baghdad, two bombs rocked the central part of the city early Friday. Police said one person was injured in a blast at the Sadeer Hotel used mainly by foreign contractors.

Another bomb was reported to have targeted a U.S. military convoy, witnesses said. There were no reports of casualties in that incident.

The U.S. military said Friday three American soldiers had been killed in action in clashes in Baghdad and the town of Iskandariyah 30 miles south of the capital.

Two members of Task Force Baghdad were killed Thursday afternoon when their patrol was struck by a roadside bomb. Another soldier was shot dead during a clash in Iskandariyah on Wednesday.

A car bomb exploded in Maghrib street in Baghdad's Sunni neighborhood Azamiyah on Friday near an Iraqi police patrol, injuring one civilian.

In the aftermath of Wednesday's mass loss of life during a Shiite pilgrimage in Baghdad, politicians from Sunni and opposition Shiite groups have denounced the government's failure to organize the processions and to quickly react following the stampede in which nearly 1,000 people died.

"This is a result of the inadequate performance of the interior and defense ministers, which has caused such a loss of life," said Baha al-Aaraji, a Shiite lawmaker allied with radical cleric Muqtada al-Sadr.

Al-Aaraji said the ministers should "stand in front of" parliament and if the legislators believe they failed in their responsibility to protect marchers, "they should be dismissed and stand trial."

The stampede erupted as hordes of Shiite pilgrims, many women and children, were jammed up at a security checkpoint established months ago to restrict movement from a Sunni neighborhood on the eastern side of the river to a Shiite stronghold on the west side.

The chaos only served to underscore how poorly prepared the Iraqi forces are to control security in the current atmosphere of violence and sectarian mistrust.