No fewer than 12 civilians died in a series of bombings in a market north of the capital, Baghdad.
Dozens of people were also wounded in the attacks, reports said.
Two car bombs went off and a suicide bomber blew themselves up in the predominantly Shia town of Judaida al-Shat in Diyala province.
Reports three parked car bombs exploded virtually simultaneously early on Monday, tearing through a wholesale vegetable and fruit market in the town of Jidaidat al-Shatt in Diala province, just outside the provincial capital of Baqouba some 60km northeast of Baghdad.
The area was recently hit by twin car bombings which killed at least 41 people outside a Sunni mosque in Baquba about three weeks ago.
Tensions between the Shia Muslim majority, which leads the government, and minority Sunnis has been growing since last year.
Sunnis have accused the government of Prime Minister Nouri al-Maliki of discriminating against them – a claim the government denies.