BAGHDAD, Feb 13: Another lethal bomb rocked central Baghdad on Tuesday, killing 16 people as security forces battled to save the credibility of a make-or-break security plan after a day of devastating attacks.

A suicide bomber detonated a van packed with explosives in a crowd outside a food warehouse in the mixed west Baghdad district of Iskan, demolishing a house and wounding at least 40 bystanders, a security official said.

“There were women and children among the victims, including 12 people from the same family killed or wounded when their nearby house collapsed,” he said, explaining that the depot is used to distribute subsidised food rations.

A surviving family member, a teenage boy in a red tracksuit, sat stunned amid the wreckage of the home, his head in his hands, sobbing. American soldiers joined their Iraqi counterparts in securing the scene.

Overnight, mortar shells had crashed into Suwaib, a suburb in the south of the city, killing three civilians, he added. Insurgents and militia fighters killed four more Iraqis in incidents in southern Iraq, police said.

Another car bomb killed four people and wounded another four near a bakery in Al-Amin neighbourhood of eastern of Baghdad, security officials said.

The carnage came despite a massive security operation by US and Iraqi forces, and one day after a series of bombings in market areas killed at least 79 people outright and saw 165 taken to hospital.

In the Mansur district traffic was funnelled onto main roads by concrete barricades and protected by Iraqi checkpoints manned by heavily-armed police and troops.

Nevertheless, many people expressed anger that the bomber got through.

“Where is this security plan?” demanded one bystander.

Brigadier General Abdel Karim Khalaf said that three suspects --including two whom he described as “Asians” -- were being interrogated after being arrested following Monday's blitz on the capital's commercial centre.

“If I told you any more, it would hurt the investigation, but we're making progress,” the interior ministry operations chief said.

The attacks -- three car bombs in a bustling wholesale trading area and an explosive device in a popular market area -- struck a terrible blow to Prime Minister Nuri al-Maliki's authority as he paraded his security plan.—AFP