An Al-Qaeda front group claimed a wave of bombings across Baghdad in a statement on Friday, part of a surge in violence sparking worries of a return to all-out bloodshed.
The Islamic State of Iraq and the Levant said the attacks carried out on Wednesday, when nationwide violence killed 75 people and wounded more than 200, were retribution for the executions this month of people convicted of terror-related offences.
The group, formerly based solely in Iraq, has since expanded its reach to neighbouring Syria, where President Bashar al-Assad has been embroiled in a 29-month conflict with rebels, of whom the Al-Qaeda group are a critical part.
"The new wave organised by the lions of the Sunni people... was a response to the crimes of the Safavid government with the executions of a group of Islamists from the Sunni people in Iraq," said the statement posted on jihadist Internet forums.
It referred to Iraq's central government using a pejorative for Shiite Muslims, referencing the former Safavid empire that ruled what is now modern-day Iran.
On August 19, Iraq put 17 people to death, all but one of them on terrorism-related charges.
"The operations were carried out despite the heavy presence of security forces, who placed tens of thousands of their donkeys and their animals just in Baghdad and around Baghdad, which as become a big, closed prison for its residents," the statement said.
Further details of the attacks would be published in future, the group said, without elaborating.
It only described the targets as "official and security and military places, and the places of the Rafidhiyah and the head of the Safavids," another negative term for Iraq's Shiite majority.
In fact, most of the targets hit on Wednesday were busy streets and markets as civilians were packed in rush hour traffic, with 71 people killed in Baghdad and nearby towns. Four others were killed in the country's north.
Iraq has seen a marked rise in the level of violence this year, coinciding with demonstrations by the Sunni Arab minority against alleged ill treatment at the hands of the Shiite-led government and security forces.
More than 600 people have already been killed so far this month, according to an AFP tally.
Diplomats and analysts have urged broad-reaching moves to tackle Sunni frustrations, which they say give militant groups room to recruit and carry out attacks.
However, Prime Minister Nuri al-Maliki has vowed to press on with an anti-militant campaign.