Baghdad, Iraq - Gunmen took aim at multitudes of Shiite Muslim worshipers marching through this besieged capital Sunday, killing at least 22 and leaving hundreds injured in a vivid illustration of the sectarian violence driving Iraq toward open civil war.
Panicked pilgrims, including women in full-length black robes, scattered in terror as opportunistic gunmen fired from positions on rooftops, inside buildings and on the streets. Security officers and Shiite militiamen returned fire during rolling gun battles along the routes to the worshipers' destination, a major Shiite shrine.
Iraqi television showed images of pilgrims diving for cover behind parked cars and buildings as ambulances ferried off victims. Authorities reported that security forces killed several of the snipers.
Despite the gunplay, U.S. and Iraqi officials argued that a draconian weekend security clampdown, including a two-day ban on most vehicular traffic in the capital, helped avert a higher death toll as more than 1 million Shiites headed on foot to the shrine. No major attack was reported at the bustling holy site.
An Interior Ministry official labeled the security dragnet, which also included the posting of thousands of police officers and troops at the shrine and along its access roads, as "an extraordinary success," given the potential for mass casualties in the incendiary climate of contemporary Iraq.
Last year, almost 1,000 pilgrims were killed during a stampede sparked by fears of a suicide attack that culminated in a human crush on the Aima Bridge over the Tigris River. Many of the victims, including numerous women and children, were forced into the river and drowned.
This year, police closed the Aima Bridge and funneled worshipers to two other spans in a move aimed at dispersing the masses and providing greater protection.
The U.S. military praised the "comprehensive security plan" devised by Iraqi military and civil leaders.
"These acts against innocent civilians are deplorable, but Iraqi security forces did an excellent job in preventing more needless loss of innocent civilian lives," Army Maj. Gen. James D. Thurman, who leads American forces in Baghdad, said in a statement.
Officials cited the lack of car bombs and suicide strikes as significant accomplishments during the two-day religious ceremony, which attracted masses of faithful to the gold-domed shrine in the northern Baghdad neighborhood of Kadhimiya. Four mortar strikes were reported in the capital, an official said, but none was fatal.
Authorities set up checkpoints as far as three miles from the shrine and searched everyone entering the holy site for weapons and concealed suicide devices. Foot patrols hunted for clandestine launching pads used to fire mortar rounds and Katyusha rockets, staples of the insurgent arsenal.
Officials said those killed Sunday were shot en route to or from the shrine as they walked through neighborhoods populated mostly by Sunni Muslims, who are fighting the country's Shiite majority in an increasingly bloody internecine struggle. Many worshipers walked for miles, some barefoot, to pay homage to Musa al Kadhim, who died more than 1,200 years ago and is one of the 12 revered imams of the Shiite sect.
Gunmen shot and killed at least seven other pilgrims along a highway on Friday, officials said, before the vehicle ban went into effect.
Authorities said 302 people were injured during this year's pilgrimage, including gunshot victims and shrapnel casualties from mortar strikes. It appeared that many were hurt in other ways, such as falling while scrambling from the gunfire.
Baghdad, whose residents long boasted of religious tolerance, is increasingly a city of Sunni and Shiite enclaves. Many have left once-mixed neighborhoods for the relative safety of zones dominated by one or the other sect and patrolled by corresponding militiamen. Others have been forced out or killed.
But many pilgrims headed to the Kadhimiya shrine had no choice but to pass through largely Sunni districts brimming with resentment about the Shiite political domination that followed the U.S.-led ousting in 2003 of Saddam Hussein, a Sunni who favored his minority sect.
"I left my house at 10 p.m. because it is much safer and the weather is cooler," said Ali Hassan, 18, a laborer who arrived safely at the shrine in the predawn hours Sunday. "But this morning we heard some gunshots aimed at the pilgrims, and some were hit."
Hassan, who was uninjured, said he made the pilgrimage in honor of his older brother, Sadeq, who perished in the Tigris during last year's human stampede.
That a day in which almost two dozen people were shot dead could be labeled a security success is a reflection of the unforgiving gauge of today's Iraq, where as many as 100 civilians are killed daily in a vicious sectarian struggle.
Extraordinary security measures, such as those imposed this weekend and during last year's elections, have managed only to curb the bloodshed for concentrated periods.
"This year there are more visitors, and the process was more organized," said one pilgrim, Saad Jabiri, a 30-year-old shop owner and father of four who walked to the shrine but returned in an ambulance accompanying a friend hit by sniper fire.
"This is a challenge to the terrorists, the Saddamists and the occupiers," said Jabiri, lumping together both the Sunni-led insurgents and U.S. forces in a formulation common among residents of Sadr City, a radicalized Shiite stronghold where he and many other pilgrims reside.
Iraq's large-scale Shiite religious celebrations, banned or otherwise held in check during Hussein's rule, have become vivid symbols of the Shiite ascendancy in recent years.
Shiite politicians and religious leaders have made no effort to limit the extravaganzas, despite the parlous state of security.
Volunteers line the pilgrimage routes, providing the faithful with water, food and glasses of sweetened tea served from steaming caldrons. Many participants chant, hoist the green-and-black flags of Islam and work their way into a religious frenzy as they approach the shrines.
In recent days, worshipers gathered at a major entrance to Sadr City, where a mural depicts victims of last year's stampede falling into the Tigris as doves fly above.
Many in the long-dominant Sunni community view the elaborate gatherings as political acts and provocations, just as many Roman Catholic nationalists in Northern Ireland resent the annual loyalist "marching season" as an affirmation of Protestant domination.
Attacks on Shiite festivities have become so commonplace that authorities have begun to devise elaborate security plans well before the pilgrims take to the streets. Religious leaders also muster throngs of Shiite militiamen to assist in the security effort.
Still, the Shiite gatherings have experienced some of the worst atrocities of the more than 3-year-old insurgency. Last year's stampede still ranks as the bloodiest day since U.S.-led forces deposed Hussein.
In 2004, during a Shiite religious festival, about 180 pilgrims were killed when up to a dozen suicide bombers mingling with pilgrims detonated their payloads at shrines in Kadhimiya and in the Shiite holy city of Karbala in coordinated strikes.