Market bombings and other attacks across Iraq killed at least 40 people on Tuesday, and one senior intelligence figure said he could not rule out that guards may have taken bribes to allow terrorists to penetrate security during a Shiite pilgrimage.
The latest attacks added to fears that Iraq is descending further into violence after the last American troops withdrew late last year. More than 275 people have died in attacks over the past month, the bloodiest period since immediately after the U.S. withdrawal.
Tuesday morning's wave of bombings struck six Iraqi cities and towns. The worst hit was Diwaniyah, 130 kilometers (80 miles) south of Baghdad, where an explosives-laden vegetable truck detonated in a crowded market. Officials said 26 people were killed and about 75 wounded.
Vegetable seller Salah Abbas, 41, described a scene of chaos after the explosion ripped through the crowd.
"There were many charred bodies on the ground," said Abbas, who rushed to help wounded fellow merchants before ambulances arrived. He managed to push one to safety in a cart, but he said two others died at the market.
"People screaming and crying — some were coming in to get their relatives, while others were running out. Then rumors spread of more car bombs, and people ran out of the market in panic," he said.
A senior Iraqi military intelligence official said there were at least two security lapses in Tuesday's market attack, and money might have changed hands.
One guard at a security checkpoint in Diwaniyah failed to properly search the produce truck because he said he couldn't stand the smell of rotting vegetables and fruit, and another guard later allowed the truck to enter the market itself instead of being unloaded outside as security rules require, the intelligence official said.
He said, "We do not rule out that bribes were paid to some at the checkpoints." The military official spoke on condition of anonymity in order to discuss sensitive matters of security.
Tuesday's attacks come as hundreds of thousands of Shiite Muslim pilgrims were heading to the holy city of Karbala this week for religious ceremonies set to peak on Friday. Shiite pilgrimages are a favorite target of Sunni insurgents linked to al-Qaida.
Attacks timed to strike during a similar march in Baghdad last month left 100 dead.
Diwaniyah is about 40 kilometers (25 miles) from Karbala, which also was hit by two bombs hidden in cars parked outside a market in the early morning, blasts that killed five people and wounded 30.
Jubair al-Jabouri, chairman of the Qadisiyah provincial council, confirmed the death toll in Diwaniyah, a Shiite city and the provincial capital. He blamed al-Qaida for the attacks.
"Terrorism has no religion," al-Jabouri said. "The terrorists targeted the innocents today in Karbala and Diwaniyah."
No one immediately claimed responsibility for the bombings.
Last month, no more than three days passed without a major attack, signaling the insurgency's ability to regroup quickly, as opposed to earlier patterns, when militants took several weeks to coordinate and gather material for an occasional, if spectacular, wave of bombings.
Despite their extra measures, security forces appear powerless to stop the violence. That has damaged the government's already shaky credibility with the Iraqi people and fanned fears the country may be spiraling out of control without recourse to American troops to restore order. The last American soldiers withdrew last December after nearly nine years of war.
Iraqi officials and experts also say the Sunni insurgents have been emboldened by a months-long sectarian-based political crisis that has all but paralyzed the government, and they now seek to exploit tensions among the country's ethnic factions.
Within hours of the two Karbala bombings, authorities banned vehicles from entering the holy city through Friday, a new step to protect the pilgrims. Karbala, 80 kilometers (50 miles) south of Baghdad, is the destination for annual Shiite rituals on the anniversary of the birth of the ninth-century Shiite leader known as the Hidden Imam.
"Al-Qaida groups are trying to stop Shiite people from practicing their rituals of the pilgrimage," said Karbala Gov. Amal-Din al-Hir. "But we are confident that the Shiite pilgrims will be undaunted by these explosions."
Bombs also struck three other cities in central Iraq, and a gunmen attacked security forces in a fourth.
In the Sunni city of Taji, two bomb blasts killed three people and wounded 15. A policeman was among the dead, said security and health officials who confirmed the casualties. Taji is home to a military base and is 20 kilometers (12 miles) north of Baghdad.
In the capital itself, two roadside bombs exploded next to security patrols in separate neighborhoods, killing a policeman and a passer-by, and wounding 14 other people, officials said.
And in Sunni-dominated Diyala province, just northeast of Baghdad, a bombing left two farmers dead, and a drive-by shooting killed two security officers and wounded two others.
The casualties were in Baghdad, Taji and Diyala were confirmed by police and health officials who spoke on condition of anonymity as they were not authorized to release the information.