A string of bomb blasts in predominantly Shi'ite Muslim provinces of Iraq killed at least 24 people on Sunday, police and medics said.
The violence is part of a sustained campaign of militant attacks this year that has prompted fears of wider conflict in a country where ethnic Kurds and Shi'ite and Sunni Muslims have yet to find a stable power-sharing compromise.
A suicide bomber killed at least four people in a Shi'ite mosque in the town of Mussayab, and in Kut city, a car bomb went off in a busy market, killing five, police and medics said.
Three bombs exploded in quick succession near the headquarters of a Shi'ite political party in the southern oil hub of Basra, 420 km (260 miles) southeast of Baghdad, killing at least eight people, police said.
"When the first explosion happened, I ran to evacuate the victims. I saw two or three burned bodies before police asked me to step back," said a man who gave his name only as Alaa. "When police forced me to move away, the second explosion happened."
Two car bombs went off in a market in Nassiriya, 300 km (185 miles) southeast of Baghdad, killing two people. Another car bomb killed four at a busy market in the Shi'ite shrine city of Kerbala, 80 km (50 miles) southwest of Baghdad, police said.
It was not clear who was behind Sunday's explosions, but Sunni Islamist insurgents, including the al Qaeda-affiliated Islamic State of Iraq, have been regaining strength in recent months, security sources say.
Sectarian tensions have been inflamed by the civil war in neighboring Syria, which is fast becoming a region-wide proxy war, drawing in Shi'ite and Sunni fighters from Iraq and beyond to fight on opposite sides of the conflict.
On Saturday, two bombings near Sunni mosques in Baghdad killed at least 23 people who had come to pray after breaking their daily fast for the holy month of Ramadan.
More than 300 people have been killed so far in July, according to the violence monitoring group Iraq Body Count.
The bloodshed has stoked fears that Iraq is sliding back into all-out conflict, though it has yet to match the sectarian carnage of 2006-07 when monthly death tolls sometimes topped 3,000.