Thousands of Shiites, many waving Islam's holy book over their heads, protested the U.S.-led occupation in Iraq on Thursday, setting off clashes in at least one southern city as they answered a call by a radical cleric to paint Israeli and American flags on the ground and stomp on them.
Sunni Muslim clerics also delivered fiery sermons in Baghdad and in cities like Ramadi, capital of the volatile Sunni Triangle in western Iraq, where more than 3,000 people protested the U.S.-led occupation in Iraq.
In a separate action, Sunni Muslims began shutting down their mosques to complain about their alleged mistreatment at the hands of the country's majority Shiites - who they have blamed for kidnapping and killing several of their clerics.
The U.S. military also launched what it said would be an aggressive investigation to discover how pictures of an underwear clad Saddam Hussein wound up on the front page of a British tabloid.
The pictures, the military said, violated military guidelines and possibly the Geneva convention on the humane treatment of prisoners. They are expected to further fuel anti-American sentiment among Iraqi supporters of the former dictator.
The protests in Najaf, Nasiriyah and Kufa, came as Iraq's Shiite prime minister, Ibrahim al-Jaafari, announced that he will visit Syria, which has been blamed for harboring insurgents bent on starting a civil war in Iraq.
In Baghdad, clashes also broke out in two northern neighborhoods across the Tigris River. In Kazimiyah, a suicide bombing targeting the house of Iraqi national security adviser, Mouwafak al-Rubaie, killed two civilians and wounded three, police said.
After the explosion, unknown gunmen in Azamiyah opened fire at a U.S. base in Kazimiyah on the western side of the river, witnesses said. The gunmen later fled, they added. Witnesses reported seeing U.S. Apache attack helicopters firing rockets into the neighborhood.
A U.S. soldier was killed early Friday in a vehicle accident caused by roadside bomb attack near Taji, 20 kilometers (12 miles) north of Baghdad, the military said. The soldier's identity was withheld pending notification of next of kin.
At least 1,628 members of the U.S. military have died since the beginning of the Iraq war in March 2003, according to an Associated Press count.
A roadside bomb also destroyed a U.S. military truck and wounded an unspecified number of American soldiers on a highway in southeastern Baghdad, said a military spokeswoman and police Lt. Mazin Saeed.
Tension was palpable throughout Baghdad, where both Sunni and Shiite Muslims have accused each other of fanning sectarian hate.
Two children were killed and their mother was injured in a bomb blast late Thursday outside a Shiite Muslim mosque in Baghdad, an army official said Friday. Targeting Mosques and clerics, both Sunni and Shiite, has been a routine practice for extremists such as Jordanian-born Abu Musab al-Zarqawi.
In Turkey, al-Jaafari said Iraq would not tolerate foreign fighters crossing the porous desert frontier that separates his country from Syria.
"There are some armed groups infiltrating from Syria..... How much of this infiltration is related to the Syrian government, we will discuss this issue directly with Syrian authorities," he said. "We will visit Syria some time soon, and one of the issues that will be taken up will be the security file and the prevention of such infiltrations."
The Syrian government has not commented on allegations that foreign fighters are both slipping into Iraq across its shared border and holding clandestine planning meetings in its country. But in February, Syria captured and handed over Saddam Hussein's half brother in what Iraq called a gesture of goodwill.
A U.S. official said Wednesday that Syria was the site of a key meeting last month in which al-Zarqawi lieutenants were ordered to carry out more attacks in Iraq. More than 520 people have been killed since the country's new Shiite-dominated government was announced April 28.
Earlier this week, al-Jaafari pledged to use "an iron fist" to prevent an outbreak of sectarian violence.
Around Sunni mosques on Friday, clerics repeated a call from three of Iraq's most influential Sunni Muslim organizations for the places of worship to be shut for three days to protest alleged Shiite violence against them.
One of those organizations, the influential Sunni Muslim Association of Muslim Scholars, on Wednesday accused a Shiite militia of allegedly killing Sunni clerics - a charge the group immediately denied.
An estimated 6,000 protesters took part in the southern demonstrations, according to Associated Press reporters at each location.
The protests followed Muqtada al-Sadr's call Wednesday to reject the U.S. occupation of Iraq by painting Israeli and American flags on the ground outside mosques to be stepped on in protest raids against holy places.
Al-Sadr, a burly, black bearded turbaned cleric, launched two uprisings against U.S. forces in Baghdad and Najaf in April and August last year. After the last uprising he went into hiding until surfacing Monday demanding an end to the U.S.-led coalition occupation of Iraq.
The call was made a day after U.S. and Iraqi forces detained 13 al-Sadr supporters during a raid on a Shiite mosque in Mahmoudiya, about 30 kilometers (20 miles) south of Baghdad. Iraqi troops confiscated weapons from the mosque.
"From this platform, we warn the government not to fight the al-Sadr movement because all the tyrants of the world could not beat it," Hazim al-Araji, the imam of a mosque in Kufa, the nearby twin city of Najaf, during the Friday Sermon. "We say to the government do not be a tyrant like Saddam (Hussein) or (former interim Iraqi Prime Minister Ayad) Allawi."
In both Najaf and Kufa, al-Sadr followers painted American and Israeli flags on most streets near mosques before stepping on them.
"Down, down Israel; down, down USA," chanted protesters following midday prayers at a Kufa mosque.
In Nasiriyah, about 320 kilometers (200 miles) southeast of Baghdad, al-Sadr supporters clashed with guards at the headquarters of Dhi Qar provincial governor, Aziz Abed Alwan.
The fighting broke out before noon as about 2,000 members of al-Sadr's al-Mahdi Amy marched toward the cleric's local office, which is near the governor's headquarters.
Armed men guarding the headquarters shot toward the crowd in an apparent bid to disperse it, prompting retaliatory fire from al-Sadr supporters, injuring four policemen and four civilian. Another nine al-Sadr supporters were injured, said Sheik al-Khafaji, an official at al-Sadr's Nasiriyah office.
Russian officials have repeatedly declared that Israeli aviation poses a threat to the Russian military in Syria.