Two roadside bombs exploded outside a mosque in the Iraqi city of Baquba killing 30 people, as Sunni Muslim worshippers were leaving following Friday prayers, police said, Reuters reported.
A further 25 people were wounded in the blasts, which went off in quick succession. The second tore through a crowd of people who had rushed to help those hurt in the first.
It was not immediately clear who carried out the attack.
More than two years of civil war in neighboring Syria have brought sectarian tensions in Iraq and the wider region to the boil.
About 800 Iraqis were killed in August, according to the United Nations, with more than a third of the deadly attacks happening in Baghdad.
The bloodshed, one-and-a-half years after U.S. troops withdrew from Iraq, has raised concerns about a return to the sectarian slaughter of 2006-07, when the monthly death toll sometimes topped 3,000.