BAGHDAD - U.S.-led forces on Friday arrested suspected Shiite militants accused of smuggling powerful bomb components from Iran, and clashes between Shiite factions broke out in two major cities. The U.S. announced the deaths of five American soldiers - three of them in bombings.
The arrests occurred during a raid early Friday in Baghdad's teeming Shiite district of Sadr City, stronghold of the notorious Mahdi Army militia of anti-American cleric Muqtada al-Sadr.
A U.S. military statement did not identify them as Mahdi Army members but said they were part of a "secret cell" that smuggles powerful bombs known as "explosively formed penetrators," or EFPs, from Iran and sends Shiite fighters from Iraq for training in Iran.
U.S. and some Iraqi officials suspect the Iranians may be stoking a growing power struggle among Shiite factions and political parties - despite the Tehran government's insistence that it is working to help bring stability to its neighbor Iraq.
Clashes broke out Friday in Baghdad and in the Shiite shrine city of Najaf when police said Mahdi Army gunmen attacked offices of the Supreme Council for the Islamic Republic in Iraq, or SCIRI, a key member of the U.S.-backed Iraqi government but with strong ties to Tehran.
Four people were injured in Najaf, 100 miles south of Baghdad, prompting local authorities to impose a curfew. The clash in Baghdad occurred when Mahdi gunmen fired rocket-propelled grenades and automatic weapons at a SCIRI office in the Habibiya district, injuring two guards, police said.
In Diwaniyah, a Shiite city 80 miles south of Baghdad, suspected Shiite gunmen attacked a joint U.S.-Iraqi patrol late Friday, killing one Iraqi soldier and wounding four civilians, police said.
It was unclear what provoked the attacks, but they appeared to be part of an escalating power struggle brewing throughout the dominant Shiite community, which intensified after Britain announced plans to draw down its troops in the mostly Shiite south.
Shiite parties are trying to oust the Shiite governor of oil-rich Basra province, and violence has broken out recently in Kut and other Shiite cities.
Some Mahdi Army members in Sadr City have said a pro-Iranian faction has been sending fighters to Iran for training. The members spoke on condition of anonymity because of fears for their own safety.
In another sign of unrest, hundreds of angry Shiites poured onto the streets of Najaf and Basra to protest what they considered insults by Al-Jazeera television against Iraq's most revered Shiite cleric, Grand Ayatollah Ali al-Sistani.
The protesters were angered by an Al-Jazeera talk show this week in which the host, Egyptian Ahmed Mansour, questioned al-Sistani's leadership credentials and whether he authored his own religious edicts.
Unrest in Shiite areas adds a new and dangerous dimension to the challenge facing U.S. forces as they try to restore order in the capital during the 11-week Baghdad security operation. U.S. officials maintain that sectarian killings in the capital have declined since the Baghdad crackdown was launched Feb. 14, in large part because Shiite militias assumed a low profile to avoid a confrontation with the Americans. But attacks using EFPs, the signature weapon of Shiite militias, are on the rise. Last month, the number of EFP attacks against American forces hit a monthly high of 69, U.S. officials said. At the same time, April was the deadliest month for U.S. troops in Iraq since December with 104 deaths, although it was unclear how many were a result of EFPs. The increase in attacks using EFPs, which the U.S. says come from Iran, suggest that the Shiite extremists may be shifting tactics, reducing their slaughter of Sunni civilians but focusing more on U.S. and Iraqi forces. This week, extremists launched at least three rocket or mortar attacks against the U.S.-controlled Green Zone, killing four Asian contractors. Those attacks appeared to have come from areas where Shiite militias operate. It was unclear whether Iranian weapons were responsible for the latest U.S. deaths. The military said one American soldier was killed Friday by a bomb south of Baghdad. Four others were killed Thursday - two by bombings in Sunni and Shiite areas of the capital and two in unspecified "combat operations" in Sunni-dominated Anbar province, the military said. A senior U.S. commander was wounded Thursday by small arms fire while inspecting a controversial security barrier being built by the military to separate a Sunni enclave from surrounding Shiite areas in northern Baghdad, the U.S. said Friday. The officer's name was not released. One Iraqi interpreter was also killed in one of the Thursday attacks in Baghdad, the military said. At least 38 other Iraqis were killed or found dead Friday, police said. They included five policemen killed in a roadside bombing in western Baghdad and five civilians who died when a car bomb exploded near a Shiite mosque in Hillah. The bodies of 16 men - bullet-riddled and handcuffed - were found in various parts of Baghdad, apparent victims of sectarian death squads, according to police. Violence has also intensified as the U.S. steps up its campaign against the Sunni-dominated al-Qaida network, which President Bush has identified as the No. 1 target of the U.S. military. American and Iraqi troops repulsed a coordinated attack near Fallujah in a three-hour battle Thursday in which 11 people were killed, six of them insurgents, the U.S. Marines said Friday. There were no U.S. troops or Iraqi police killed, the Marines said, but five civilians died, five Iraqi police were wounded and one policeman was missing. On Thursday, the U.S. announced it had killed al-Qaida propagandist Muharib Abdul-Latif al-Jubouri in a battle near Taji north of Baghdad. On Friday, U.S. officials said al-Jubouri's spiritual adviser, Sabah Hilal al-Shihawi, and Egyptian fighter Abu Ammar al-Masri were also killed in the same battle. But the two top al-Qaida figures - Abu Ayyub al-Masri and Abu Omar al-Baghdadi - remain at large. Iraqi officials had announced both had been killed, apparently confusing them with al-Jubouri. Al-Qaida's front organization, the Islamic State of Iraq, denied either was dead in separate statements posted on Islamic extremist Web sites. AP-CS-05-04-07 1710EDT