Baghdad, Iraq ? Sunni Muslim clerics closed several mosques here after Friday prayers and thousands of Shiite Muslims took to the streets in several Iraqi cities, both in protest to assassinations and sectarian violence that have left more than 400 dead in recent weeks.

The Muslim Clerics Assn., an influential Sunni group, called for the three-day closure of the mosques, protesting what the groups said was violence against them by Shiites.

“In spite of all these tragic incidents, we are still calling for self-restraint, and that reason and calmness would prevail,” said the Sunni Sheik Ahmad Abdul-Ghafoor Samarrai during Friday’s prayer. He called upon the Iraqi government to investigate alleged violence against Sunnis before the security situation will “deteriorate even more.”

The protests came amid continued violence around Baghdad.

A rocket attack wounded five detainees, three of them seriously, at Abu Ghraib prison just outside the capital, according to the U.S. military. The military also confirmed that an American soldier was killed Thursday in a roadside bombing north of Baghdad.

Iraqis leaving the al-Jumhuriyah mosque walk over U.S. and Israeli flags, heeding a call by Shiite cleric Muqtada al-Sadr to paint Israeli and American flags on the ground in front of mosques for people to step on, in the southern town of Basra in Iraq. Sunni Muslim clerics closed several mosques after Friday prayers and thousands of Shiite Muslims protested in the streets.

At the city’s Bratha Mosque, a mortar round hit an area behind the building Friday afternoon while more than 1,000 people were gathered to attend the prayers. Worshippers could hear gunshots outside, and started chanting, “Death to the Baathist” and “God is the greatest.” Sheik Jalaluddin Saghir, who was leading the prayers, asked people to return to their knees, since it is not allowed to stand during prayer, according to an witness.

Elsewhere in Baghdad, an Iraqi National Guard patrol was driving along a street along the western bank of the Tigris River when a parked car exploded, killing two people. Other Iraqi forces rushed to the scene. Heavy shooting erupted between two neighborhoods divided by the river, according to police and witnesses.

Apache helicopters sent in by the U.S. military fired at the neighborhood on the eastern bank, causing several house fires, according to a policeman.

Afterward, American Humvees patrolled the empty streets.

– Times staff writers Saif Rasheed, Shamil Aziz, Raheem Salman and Suhail Ahmad contributed to this report.