As many as five suicide bombers killed 12 people on Sunday at an Iraqi army complex, the military said, in the first major strike in Baghdad since the US army declared an end to combat operations last week.
The coordinated attack occurred in the morning at the rear gate of Rusafa military command headquarters in the centre of the capital, which only three weeks ago was hit by a massive suicide bombing that killed dozens.
Accounts varied between witnesses and security force members, but the capital's security command said five suicide attackers had approached the compound in a minibus.
"One of them stepped out of the minibus, and security forces fired at him and he exploded," Baghdad operations command said in a statement.
"Two others fled to a nearby building, and the minibus exploded with the two remaining terrorists inside. Security forces cordoned off the building and traded fire with the last two terrorists until both of them blew up."
A policeman who was wounded at the scene of the attack told AFP he had seen one vehicle bomb and a suicide attacker blow himself up, as well as gunfire between insurgents and security forces.
Baghdad operations command, which is also based in the complex that was attacked, put the toll at 12 dead and 36 wounded from the attack.
A defence ministry official, speaking on condition of anonymity, said that 11 people had been killed. It was unclear how many of the victims were soldiers.
"I was waiting with three of my colleagues near an armoured car (when the attack occured)," a policeman told AFP on condition of anonymity from the hospital, slumped against the wall of the emergency room with bandages covering gunshot wounds to both of his legs.
"I was shot in two places, and I tried to hide behind the car. When I looked for my colleagues again, they were not there -- all I saw was blood and the vests that they had set aside."
The policeman, visibly shaken, added that the vehicle that exploded was a red car that passed through a preliminary search before exploding at a second checkpoint.
"It was a suicide attack," he said, noting that he had also seen gunmen fire at soldiers and a suicide bomber blow himself up.
The largest blast sent plumes of smoke into the skies over the capital, with nervous soldiers frisking any civilians who crossed Bab al-Muatham bridge, which connects the west side of Baghdad to Rusafa in the east.
The explosion caused extensive damage to nearby buildings and Dr Adil Saloom, director of the hospital's emergency department, said 20 patients had been treated.
Adil Kadhim, an emergency room nurse, said most of the victims had suffered fractures, gunshot wounds and trauma.
Soldiers refused to allow people to pass by the site of the attacks, reporting a persistent stream of single gunshots in the area, which they described as sniper fire.
The Rusafa military headquarters, responsible for security on the eastern side of Baghdad, was being used as an army recruitment centre on August 17 when a suicide bomber detonated his payload, killing 59 people.
Sunday's explosion was the biggest to hit Baghdad since the recruitment centre attack and it came four days after US forces officially transformed their role in Iraq from a combat mission to "advise and assist" operations.
While nearly 50,000 US troops remain stationed in Iraq, US Vice President Joe Biden launched the new mission while visiting Baghdad last week, opening up a fresh phase in a seven-year deployment that has cost the lives of more than 4,400 American troops.
He said in a speech on Wednesday that violence in Iraq was now at its lowest level since the war, but that same day official statistics said 426 people died in unrest last month, underscoring insurgents' continuing ability to kill.
The apparent spike in violence -- July was Iraq's deadliest month in more than two years -- comes amid a political impasse in which no new government has been formed since a general election in March.

Copyright 2010 AFP Global Edition