BAGHDAD (Reuters) - A series of bombs tore through crowds of Shi'ite pilgrims celebrating a major ritual across Iraq on Monday, killing at least 32 people, mostly women and children, and wounding scores more, local police and witnesses said.
The attacks, at the height of Ashura, which commemorates the death of Prophet Mohammad's grandson Imam Hussein and defines Shi'ite Islam, underscored Iraq's fragile security as the last U.S. troops withdraw from the country by the end of the year.
In the first attack, a car bomb blasted the end of one procession in the city of Hilla, killing 16 mainly women and children, wounding 45 others and leaving bloody pools, shoes and torn clothes scattered across the street, police and witnesses said.
"A powerful and horrible explosion went off behind us, smoke filled the area," said Hadi al-Mamouri, who was taking part in the ritual. "I could only hear the screams of women and I could only see the bodies of women and children on the street."
A second attack involving two roadside bombs killed at least six more people at another procession in Hilla and wounded 18 more, police sources said.
"I was shopping nearby, and suddenly a bomb went off as the procession reached the intersection. People were scattered on the ground and everyone started rescuing the injured," Ammar Hussein, 55, said at the scene of the second blast.
Authorities in Hilla imposed a city-wide ban on cars to help prevent more attacks.
Hilla, 100 km (60 miles) south of Baghdad, is a mainly Shi'ite city on a route used by pilgrims visiting Shi'ite holy sites to the south.
In Baghdad, at least 11 people were killed and 38 more wounded by roadside bombs targeting Shi'ite pilgrims in three different neighborhoods, police and hospital sources said.
On the outskirts of Baghdad, gunmen using hand grenades attacked Shi'ite pilgrims marching to the holy city of Kerbala, killing two and wounding four in Latifiya, police said.
Hundreds of thousands of pilgrims from across Iraq, along with thousands of foreign pilgrims, most dressed in black, streamed into the city of Kerbala to mark Ashura, a ritual in which the faithful beat their heads and chests to mourn the slaying of Imam Hussein at the battle of Kerbala in 680.
Security officials assigned thousands of police officers and soldiers to protect the pilgrims as they headed to Imam Hussein's shrine in Kerbala. No major violence was reported in Kerbala amid tight security.
Monday's attacks came as the last 10,000 American troops prepare to withdraw by the end of 2011, more than eight years after the invasion that ousted Saddam Hussein and allowed the country's Shi'ite majority to ascend to power.
Violence in Iraq has eased since sectarian strife took the country to the brink of civil war a few years after the invasion. But Sunni Islamists tied to al Qaeda and Shi'ite militias still carry out deadly attacks almost daily.
On Monday, an Iraqi Sunni Muslim insurgent group with links to Saddam's banned Baath party vowed to continue attacks on U.S. personnel staying in Iraq even after troops withdraw.
Sunni Islamist insurgents often target Shi'ite shrines and ceremonies in an attempt to inflame sectarian tensions still simmering close to the surface in Iraq.
Iraq's security forces say they are generally ready to contain the stubborn insurgencies, but they acknowledge gaps in their abilities such as air defense and intelligence gathering once the American military depart.
Reporting by Baghdad newsroom; Writing by Patrick Markey and Rania El Gamal; Editing by Louise Ireland