Car bombs ripped through Shia and Kurdish targets in Baghdad and other cities Wednesday, killing at least 66 people, wounding more than 200 and feeding growing doubts that Iraq will emerge as a stable democracy after decades of war and dictatorship.

The latest bloodshed comes against a backdrop of sharpening political divisions that show Iraq has made little progress in healing the breach among its religious and ethnic communities that once pushed the country to the brink of civil war. The co-ordination, sophistication and targets of the attack bore the hallmarks of al-Qaeda and its Sunni militant allies seeking to exploit these tensions.

Some media outlets said the death toll was even higher, with the BBC saying at least 84 people were killed and the New York Times citing officials who put the death toll at 90.

Iraqi authorities played down any suggestion that the devastating attacks that have taken place every few weeks or so since the U.S. military withdrew in mid-December portend a return to the all-out, tit-for-tat violence that tore the nation apart in 2006-07.

"Iraqis are fully aware of the terrorism agenda and will not slip into a sectarian conflict," said Baghdad military command spokesman Col. Dhia al-Wakeel.

But Iraqi authorities have been unable to prevent such wide-scale attacks, even though they were on high alert during a major Shia pilgrimage. And the number and distribution of these bombings demonstrate the strength and resilience of the Sunni militants.

'I fell on the ground. Then so many people fell on me.' —Falah Hassan

Altogether, 17 explosions struck Baghdad and six other cities and towns some 500 kilometres apart, from Mosul in the vast deserts of the north to Hillah in the fertile plains of the south.

Most targeted Shia pilgrims between 5 a.m. and 8 a.m. local time as hundreds of thousands were making their way on foot to the capital.

"I fell on the ground. Then so many people fell on me" said Falah Hassan, who was being treated for wounds at Sheikh Zayid Hospital in Baghdad

Hours after the bombing in Hillah, puddles of blood and shards of metal still clogged a drainage ditch. Soldiers and dazed onlookers wandered near the charred remains of the car that exploded, gazing at the gaping holes in nearby shops.

Wednesday's blasts were the third this week targeting the annual pilgrimage to observe the eighth-century death of Imam Moussa al-Kadhim, a revered saint who was the Prophet Muhammad's great-grandson.

The processions of the faithful, many waving green banners, will converge on a golden-domed shrine in Baghdad's northern neighbourhood of Kazimiya. The commemoration culminates on Saturday.

Bombs also hit pilgrims in the cities of Taji near the capital and Karbala and Balad in southern Iraq. The Kurdish ethnic minority was also targeted: Bombs struck the offices of two political parties in the northern city of Kirkuk.

One senior Iraqi intelligence officer acknowledged that the attacks — despite heightened security measures — showed the weakness of the military and police.

Another officer, the chief of military intelligence, said the carnage could have been even worse if security forces had not managed to seize two explosives-laden vehicles in Baghdad and Taji early in the morning, including a truck full of watermelons hiding nearly a tonne of explosives. Both officials spoke on condition of anonymity to protect their families.

Deadly day

The overall toll made Wednesday the deadliest day in Iraq since Jan. 5, when a wave of bombings targeting Shias killed 78 people in Baghdad and outside the southern city of Nasiriyah.

The level of violence has dropped dramatically in Iraq since the height of the war, though Shia religious events are often targeted. Blast walls have come down, and the recent opening of a department store has given some hope to residents of the formerly terrifying Baghdad neighbourhood of Azamiyah.

Other deadly attacks since Dec. 18:

Dec. 22, 2011: Attacks rip through markets, cafés and government buildings in a dozen mostly Shia neighbourhoods of Baghdad, killing 69.

Jan. 5, 2012: Co-ordinated bombings target Shia Muslims, killing 78 in Baghdad and outside Nasiriyah, days before a Shia holy day.

Feb. 23: Attacks kill at least 55 people as car bombs go off near an elementary school in Musayyib, a restaurant in the Shia area of Kazimiyah, and by security forces and at checkpoints and around government and political offices.

March 20: Insurgents intent on derailing an Arab League meeting in Baghdad unleash attacks across Iraq, leaving 46 dead.

April 19: Bombs rip through 10 Iraqi cities, killing at least 30.

June 4: Suicide bomber detonates explosive-rigged car outside Iraq's main religious affairs office for Shia Muslims, killing 23.

But the weakness of Iraq's security apparatus, the government's inability to provide even basic services like electricity and the dysfunctional political scene foster pessimism. Six months after the departure of the last U.S. forces, the prospects of Iraq quickly transforming into a functioning democracy are further dimming.

Prime Minister Nouri al-Maliki, a Shia, is under fire for breaking promises to share power with his partners in a unity government and focusing on settling old scores. Tensions spiked after Vice-President Tariq al-Hashemi — the highest-ranking Sunni in Iraq's leadership — was charged with running death squads. The government began his trial in absentia with al-Hashemi out of the country.

"The al-Qaeda elements in Iraq are feeling like they are in a position to try to start something bigger in Iraq and they are trying to do so. They are increasingly going after Shiite targets to try to reignite the civil war," said Kenneth Pollack, a senior researcher at the Brookings Institution's Saban Center for Middle East Policy.

Meanwhile, a lethargic parliament has failed to take up important bills such as regulating the sharing of oil revenue with the northern Kurdish region. Red tape stifles economic growth. And Sunnis complain of discrimination and disenfranchisement.

Iraq's oil riches — an income of tens of billions of dollars a year — are effectively cushioning the lack of effective government and preventing the country from becoming a failed state like Somalia.

Still, despite the political crisis, there are some signs of progress that attacks like Wednesday's have not managed to erase, said Joost Hiltermann, deputy Middle East program director for the International Crisis Group.

"These attacks will occur regardless, whether there is political tension or there is no political tension," Hiltermann said.    

He noted that al-Maliki, for all his missteps, is still in control of the government and that the tensions, while escalating, have not yet shown signs of a return to the sectarian battles of the past, when bombings and attacks happened several times a day and people were afraid to leave their homes.

"The political parties are still agreeing to work out their problems through a democratic process," he said. "That's why there's talk of a no-confidence vote in parliament and not about shooting people."