At least 24 people were killed and more than 28 others wounded in back-to-back bombings in the Iraqi capital on Thursday, local media reported.
Another explosion in the town of Mahmoudiya, south of Baghdad, killed three police officers and wounded six others, according to the Iraqi National News Agency NNA, DPA reported.
Iraq has witnessed near-daily attacks since US troops withdrew in December 2011, raising fears of a return to the sectarian tensions that drove the country close to civil war in 2006 and 2007.
The violence comes at a time of a widening crisis between the Shiite-led government and the country's Sunni minority.
Earlier Thursday, Deputy Prime Minister Hussein al-Shahristani said some 4,000 prisoners have been released since the beginning of the year, in an apparent move by the Iraqi government to quell protests in Sunni areas of the country, NNA reported.
One of the key demands of the protesters, who have been demonstrating for weeks, include the release of prisoners which they say have been detained unfairly.
Al-Shahristani announced the figure during a ceremony marking the release on Thursday of 160 prisoners.
Thousands of Sunni protesters have been rallying for more than two months against Shiite Prime Minister Nuri al-Maliki, demanding a repeal of laws they claim target Sunnis.