Insurgents killed 149 Shia pilgrims heading for the holy Iraqi city of Kerbala today, including 115 when two suicide bombers blew themselves up in one of the deadliest attacks of the 4-year war.
The attacks, just over a year after the bombing of a Shia shrine in the city of Samarra, are likely to increase sectarian tensions between majority Shia and Sunni Arabs that are pushing the country to the brink of all-out civil war.
Eye witness to today's bomb attack in Hilla
Two suicide bombers strapped with explosives detonated themselves almost simultaneously in a busy street lined with tents in the city of Hilla, south of Baghdad, killing 115 people, local hospital officials said.
The tents had been set up to offer food, drink and resting areas for pilgrims. At least 200 people were wounded in that attack, the hospital officials said.
"I saw one of the suicide bombers. He was about 40 years old. He blew himself up and I saw parts of bodies flying around," a witness, who declined to give his name, said.
Another witness described scenes of chaos, with sandals and tattered clothes lying among pools of blood and tents on fire. "I watched the second bomber run into the crowd and blow himself up. Everyone around him was shredded to pieces," the witness said.
Shia Prime Minister Nuri al-Maliki blamed Sunni militants and supporters of executed former president Saddam Hussein for the "barbaric crime", according to a statement from his office.
US President George W. Bush insisted today a new security plan in Baghdad was making gradual progress, despite the killing of nine US soldiers north of the capital in two separate bomb attacks yesterday.
More than 3,185 American soldiers have died in Iraq since the US-led invasion in March 2003. Defending his plans to deploy 21,500 more US troops to Iraq, Mr Bush said in a speech to the American Legion veterans organisation: "The mission is America's mission and our failure would be America's failure."
Security in Hilla is tight for fear of a repetition of suicide bombings and attacks on Shia religious rituals by suspected Sunni insurgents of the sort that killed 171 people in Baghdad and Kerbala in March 2004.
Insurgents also launched attacks on pilgrims in and around Baghdad, again defying Mr Maliki's crackdown. Among those attacks, a car bomb in the southern Baghdad district of Doura killed 12 people, police said.
Masses of Shia pilgrims are heading to Kerbala on foot and by bus to commemorate Arbain, the end of a 40-day mourning period since Ashura, which marks the death of Prophet Mohammad's grandson in 680.
Kerbala, one the holiest cities in Shia Islam, lies 110 km south of Baghdad. Hilla is nearby.