A suicide bombing in Iraq killed at least 11 people and quickly shattered a brief period of quiet mourning Thursday, just one day after Baghdad's bloodiest day since the U.S. troop surge nine weeks ago.

The death toll from a wave of four bombings on Wednesday climbed to nearly 200 by Thursday, as families retrieved bodies from hospital morgues and passersby gawked at a giant crater left by the force of a market bomb.

But the time for mourning was cut short when a suicide car bomber rammed a parked fuel tanker in central Baghdad's Jadirya neighbourhood, killing 11 and injuring dozens, police said. The death toll is expected to rise.

Among the 140 civilians killed in Wednesday's food market attack were construction workers rebuilding the market, which had been destroyed after a bombing in February left 137 dead.

Wednesday's market bombing was the deadliest in a string of attacks that day and appeared to be meticulously planned to strike at the only exit point for construction workers from the worksite. The blast went off at 4 p.m., at the precise hour when the men were widely known to depart, and torched a lineup of buses waiting to transport them home.

Officer in charge of security arrested

Brig.-Gen. Qassim al-Moussawi, the Iraqi military spokesman, said: "We have not seen such a wave of attacks since the security plan began. These are terrorist challenges. Ninety-five per cent of those killed today were civilians."

Late Wednesday, police following orders from Prime Minister Nouri al-Maliki arrested the army commander in charge of securing the Sadriya district, where the food marked is located.

The arrested Iraqi officer's name was not released, but sources said he was in command of the 2nd Brigade of the Iraqi army's 2nd division and will face a committee investigating the bombings.

U.S. military blames al-Qaeda

Al-Maliki condemned Wednesday's attacks in an official statement: "Our Iraqi people are being subjected to a brutal attack that does not differentiate between an old man, a child or a woman," it said.

"This targeting of civilian populations brings back to our minds the mass crimes and genocide committed by the Saddamist dictatorial regime," saidthe statement from al-Maliki's office.

Besides the market attack, bombs struck Shia targets in the capital at a police checkpoint, near a hospital and on a small bus.

U.S. Defence Secretary Robert Gates called the bombings "horrifying" and accused al-Qaeda of being behind them.

In a late-night phone interview, U.S. military spokesman Maj.-Gen. William Caldwell also linked the attacks to al-Qaeda.

Rise instunning attacks in Baghdad

Nationwide, the number of people killed Wednesday or found dead was 233, which was second only to a total of 281 killed or found dead on Nov. 23, 2006. Those figures are according toAssociated Pressrecord-keeping, which began in May 2005.

U.S. officials have reported a decrease in sectarian killings in Baghdad since the U.S.-Iraqi security crackdown was launched Feb. 14.

But the past week has seen severalstunning attacks in the capital, including a suicide bombing inside parliament and a powerful blast that collapsed a landmark bridge across the Tigris River. The number of bodies dumped in the streets of Baghdad also has risen significantly.

With files from the Associated Press