KARBALA, Iraq (Reuters) -- Twin car bombs killed at least 40 people and wounded 145 others today in Iraq's holy city of Karbala as hundreds of thousands of Shi'ite pilgrims observed a major religious rite, health officials said.
The attack on the final and most important day of the Arbain festival was the third major strike this week against Shi'ite pilgrims amid a political furore over the banning of candidates, many of them Sunnis, from a March 7 election.
"We were walking back home in groups after we finished our rites and all of a sudden a huge explosion happened. I saw the balls of fire and smoke rise from the scene ahead," said pilgrim Muhammad Nasir, 31, a day laborer being treated at a hospital. "People were running away. Security forces cordoned the scene off. There were pieces of flesh scattered around."
A senior health official in Karbala, who spoke on the condition of anonymity, said that 40 bodies had been brought in to the main hospital. Other sources put the death toll at 31.
Mehdi al-Fatlawi, a medic at the city's al-Hussein hospital, said: "Bodies in plastic bags, some beyond recognition, and many others wounded. The hospital wards were full of wounded."
Police said the bombings occurred to the east of the city, which lies 80 kilometers south of Baghdad. Details were sketchy as most officials were observing Arbain, which marks the end of 40 days of mourning for Imam Hussein, a grandson of the Prophet Muhammad, who died in a 7th-century battle at Karbala.
Overall violence in Iraq has fallen, but Shi'ite gatherings remain a target for Sunni Islamist insurgents. Militants have also made a series of suicide assaults on Baghdad since August aimed at undermining Shi'ite Prime Minister Nuri al-Maliki.
Banned under Saddam Hussein, Arbain and other Shi'ite religious events have drawn millions of Shi'ites, not just from Iraq but also from nearby countries like Iran since the Sunni dictator was ousted in the 2003 U.S. invasion.
A bomb planted on a cart pulled by a motorbike killed at least 20 pilgrims on February 3 as they streamed into Karbala. More than 40 were killed outside the capital on February 1 as they began the long walk to Karbala.