An al-Qaeda front group has claimed responsibility for a wave of attacks that killed dozens of people during the Eid al-Fitr holiday.
Iraqis are blaming authorities for failing to prevent the violence.
The international community has roundly condemned the attacks, which killed 74 people and wounded more than 320 people, but almost all senior Iraqi officials, including Prime Minister Nuri al-Maliki, made no mention of the unrest.
Saturday's violence, which struck during the Eid al-Fitr holiday marking the end of Iraq's deadliest Muslim holy month of Ramadan in years, was the latest in months of bloodshed that have sparked fears of a return to the all-out sectarian conflict.
Al-Qaeda front group the Islamic State of Iraq and the Levant claimed the violence in a statement posted on jihadist forums on Sunday.
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"The Islamic State mobilised ... in Baghdad and the southern states and others to convey a quick message of deterrence on the third day of Eid al-Fitr" in response to security forces operations, the group said.
"They (Shiites) will not dream of security during night or day, during Eid or other" days, it said.
The attacks came just weeks after assaults on prisons near Baghdad, also claimed by the al-Qaeda front group, freed hundreds of prisoners including leading militants, prompting warnings and a surge in violence.
Authorities, though, have highlighted major security operations - among the largest since US forces departed in December 2011 - which they say have led to the killing or capture of many militants.
But whatever gains the operations made, they did not stop Saturday's bloodshed, and nine people were killed in fresh violence around the country on Sunday.
Violence in Iraq has increased markedly this year, with analysts saying the upsurge is the result of anger among the Sunni Arab minority that the Shiite-led government has failed to address, despite months of protests.
Human Rights Watch, meanwhile, urged Iraqi authorities to "end draconian responses" to attacks, including torture of suspects, coerced confessions and convictions based on secret testimony.
