Chain-reaction blasts triggered by three cars rigged with bombs killed at least 79 people, obliterated dozens of vehicles and sent black clouds soaring over Baghdad on Monday.

The strike in the heart of the Iraqi capital came on the first anniversary, as marked on the Muslim lunar calendar, of the attack on the Golden Dome in Samarra. The 2006 bombing of the Shia mosque, carried out by al-Qaeda in Iraq, led to the wave of sectarian killing that has consumed Iraq ever since.

Iraqis carry a stretcher at the entrance to a burning building after a car bombing in central Baghdad on Monday.
(Khalid Mohammed/Associated Press)

The explosions — set off by three cars within 180 metres of one another — occurred in quick succession and wounded 165 people near the Shorja market district, police said. The blasts levelled a building, triggered dozens of secondary explosions and set fire to several nearby stores.

About half an hour earlier, at about 11:50 a.m., a suicide bomber wearing a dynamite vest blew himself up and killed nine people milling about a popular falafel stand. That blast in the crowded Bab al-Sharqi area wounded 19 people, police said.

To many Baghdad residents, the blasts on Monday were clearly meant to coincide with last year's attack on the Golden Dome mosque in Samarra.

Prime Minister Nouri al-Maliki called for a 15-minute sit-in to commemorate the Samarra attack, and urged citizens to "chant 'God is great' in all the mosques, and to ring bells in all the churches."

Iraq's top Shia cleric, Grand Ayatollah Ali al-Sistani, called for restraint from fellow Shias on Monday's anniversary.

"We call on the believers to express their emotions but to be cautious and act disciplined, and not to do anything to hurt our brothers, the Sunnis," he said, adding "they are not responsible for this awful crime."

With files from the Associated Press