When Nazar Al-Nuaimi woke up one morning in 2006 and found three of his fellow Sunni neighbors lying dead on his doorstep in a Shiite neighborhood of the Iraqi capital, he knew it was time to go.

Rushing his wife and three children out of the house, the Sunni Arab family left behind their belongings and fled to a predominantly Sunni neighborhood across town for shelter from a wave of sectarian killings that killed tens of thousands.

Three years later, speaking from his rented home in Hay Al-Jamiaa, he is confident a rash of major bombings targeting Shiites won’t trigger revenge killings of Sunnis, as they did before, and plunge Iraq back into all-out sectarian war.

But Nuaimi, like other Iraqis, does not expect peace. He expects there will be a different type of violence ahead, one motivated by politics and the jockeying for influence and power sure to take place before national elections late this year.

“Everyone is dreaming of a new start. But I believe that the recent bombs have started the clock on a new round of attacks.”

Attacks on Thursday and Friday, killing 150 people and targeting in large part Shiite pilgrims from Iran, and other bouts of violence have created an air of dread in Baghdad, where in recent months a degree of normality had started to be felt.

The government of Prime Minister Nuri Al-Maliki, whose influence has grown in the last year as Iraqis credit him for improving security, says the bombings will not unravel what has been accomplished since the dark days of 2006-2007. But the bloodshed, shortly before US combat troops are due to withdraw from Iraqi cities, is an ominous reminder of the damage that even weakened militant groups can inflict.

“Even in the best of scenarios there is likely to be an increase in violence in the near term,” said Michael Wahid Hanna, an analyst at the New York-based Century Foundation. “The question is whether this will catalyze a broader spiral of violence or whether the security forces will be able to keep violence at manageable levels,” he said. The withdrawal of US troops worries some Iraqis, who lack trust in their own security forces and fear it could open the door to an invigorated insurgency or a torrent of revenge.

US President Barack Obama has promised to pull out combat troops from Iraq by the end of August 2010, and all US troops are due to leave by 2012.

“We are doing our utmost ... to ensure there is no vacuum when that happens and that security is viable ... but this ultimately will be an Iraqi responsibility,” Iraqi Foreign Minister Hoshiyar Zebari said on Saturday during a visit by US Secretary of State Hillary Clinton. Lubna Khadhem, a Shiite shopowner who lives in a mainly Sunni neighborhood in western Baghdad, wonders how long it will be before she finally feels safe. “I don’t know where they’ll strike next. They seem to target crowded places, and I have two children at university. What if they start attacking schools?” she asked.

Some believe the mass migration that took place because of sectarian killings has helped to reduce bloodshed by making Baghdad far more segregated along sectarian lines. Now, there are fewer areas of mixed Sunni and Shiite populations. Yet, while violence has dropped sharply in the past year, political rapprochement has proceeded haltingly at best.

Many of Iraq’s challenges have barely been addressed, such as who will control oil resources and how to enact laws allowing ex-members of Saddam Hussein’s Baath party back into government.