An avalanche of car bomb attacks on Shiite districts of Baghdad slaughtered 172 people on Wednesday and delivered a savage blow to the credibility of a two-month-old US security plan.
The series of blasts was the deadliest in the Iraqi capital since the launch of the massive crackdown; the single most devastating blast alone killed 122 people, mainly commuters and shoppers.
The bombings ripped through five districts of the sprawling capital, where 80,000 Iraqi and US troops are straining to enforce order and contain the daily violence terrorising Baghdad's five million residents.
In the bloodiest attack, a parked car exploded on a principal intersection and in a busy market area in the downtown district of Al-Sadriyah, scattering charred corpses among a row of burnt-out buses.
After a deafening blast that sent a dense cloud of putrid black smoke spewing into the sky, a fire incinerated human flesh, cars and vehicles as rescue workers converged through the streets.
Firefighters doused nearby cars and buses, as dozens of ambulances and pick-up trucks ferried the wounded to hospital and civilian volunteers wrapped charred bodies in carpets for transport to the city's overflowing morgues.
Angry Iraqis who lost loved ones lashed out at Iraqi Prime Minister Nuri al-Maliki, blaming his beleaguered government for failing to bring law and order to the streets of the capital, nearly a year after it took office.
"Down with Maliki! Where is the security plan? We are not protected by this plan," they shouted, as an angry mob pelted stones at Iraqi and American soldiers who scrambled to the scene.
A defence ministry official put the Sadriyah blast death toll at 172 with another 155 people wounded.
US Secretary of Defence Robert Gates vowed that Washington would persist with the security plan, saying a spike in violence was to be expected.
"We have anticipated from the very beginning... that the insurgency and others would increase the violence to make the people of Iraq believe the plan is a failure," Gates said in Tel Aviv.
"We intend to persist to show that it is not," he said.
On February 3, a truck bomb detonated in the same Baghdad market, a mixed Kurdish and Shiite area, killing at least 130 people in the final days before the crackdown was officially launched on February 14.
Markets are favourite targets for bomb attacks, the trademark tactic of Sunni extremists bent on slaughtering Shiites, the majority community in Iraq that today heads the government and dominates the security forces.
US military spokesman Major General William Caldwell said that troops, as part of the security crackdown, had constructed walls around vulnerable markets in a bid to thwart bomb attacks.
Another car bomb attack killed 28 people, ripping through civilians on the streets near an Iraqi army checkpoint in Baghdad's slum district of Sadr City and wounding another 44 people.
The crowded district is a bastion of Shiite militia faithful to radical cleric Moqtada al-Sadr and has frequently been targeted by car bombings blamed on Sunni extremists.
At least 11 civilians were killed and 12 wounded, including women and children, when a car bomb exploded on a main road near a private hospital in the central Karrada district, formerly upmarket but fallen on hard times.
Eleven other people, including four policemen, were killed in separate car bomb attacks elsewhere in the capital.
On top of the Baghdad carnage, five people were killed elsewhere in Iraq and police found 18 corpses in Baquba, north of Baghdad, riddled with bullets and bearing torture marks, a sign of sectarian killings, a security official said.
Another eight bodies were found in Mosul and four in Kirkuk.
Wednesday's bloodshed overshadowed a festive ceremony in southern Iraq that saw government forces assume security control of the oil-rich Maysan province from British forces as part of plans in London to drawback troops.
Reading greetings from Maliki, national security adviser Mowaffaq al-Rubaie expressed hope Iraq would take full charge of all 18 provinces before the year-end as Maysan became the fourth to pass from foreign security control.
British Prime Minister Tony Blair announced in February that the number of British troops in Iraq would likely drop to 5,000 by the end of the year, compared to about 7,200 currently deployed in the country.
