A truck bomb at a crowded market in central Iraq killed 25 people on Tuesday while attacks elsewhere in the country claimed seven lives, the latest victims of a spike in nationwide unrest.
The attacks, most of which were in predominantly Shiite areas, came ahead of commemoration ceremonies on Friday for the birth of a key figure in Shiite Islam, and left nearly 100 people wounded.
The 10:15am (0715 GMT) blast struck a popular market in Diwaniyah, 160 kilometres south of Baghdad, killing 25 people and wounding 70, a police colonel told AFP on condition of anonymity.
A hospital official in the city confirmed receiving 25 dead.
Shortly afterwards authorities imposed a curfew across the city of some 440 000 people.
Women and children were among the victims of the attack that hit the main vegetable market of Diwaniyah, where 15 shops and stalls were destroyed, the officials added.
The blast came just hours after near-simultaneous car bombs targeting Shiite pilgrims on the outskirts of the central shrine city of Karbala killed four people.
The 7am (0400 GMT) attack struck the village of Freyha, 10 kilometres east of Karbala.
"There were four killed and 13 wounded by two car bombs at around 7am, east of Karbala," provincial police spokesperson Lieutenant Colonel Ahmed al-Hasnawi said.
A medical official in Karbala, speaking on condition of anonymity, put the toll at four dead and 33 wounded.
Karbala is frequented by Shiite pilgrims as it is the site of shrines to Imam Hussein and his half-brother Abbas, both central figures to Shiite Islam.
Friday's ceremonies are to mark the birth of another figure, known as the 12th imam, and pilgrims visiting the city are frequent targets of Sunni insurgents.
"A large number (of pilgrims) will travel to Karbala this week and radical groups such as al-Qaeda ... may try to attack them in an attempt to inflict numerous casualties and enflame inter-communal tensions," John Drake, an analyst with private security firm AKE Group, warned in a statement on Tuesday.
North of the capital in Taji, a policeman was among two people killed in simultaneous bomb attacks, an interior ministry official said. A hospital official said three people died in the blasts.
The first explosion was followed closely by a second blast as police rushed to the scene, the ministry official said, adding that 14 people were also wounded, eight of them policemen.
Another bomb attack in the town of Tuz Khurmatu, north of Baghdad, killed a policeman and wounded another, an officer and a local doctor said.
The violence comes amid a spike in attacks in Iraq, with the country suffering a wave of unrest in June that left at least 282 people dead according to an AFP tally, although government figures said 131 Iraqis died.
While violence in Iraq has declined dramatically since its peak in 2006-2007, attacks remain common across the country.