Bomb attacks on Shia Muslim targets in three Iraqi cities have left at least 19 people dead and many more injured.
The first attack targeted Shia pilgrims in Karbala, south of Baghdad, killing seven people. Hours later, an explosion in nearby Najaf killed at least another seven people.
Iranian pilgrims were among the dead and injured.
Later, a car bomb attack in Basra's south-western Qibla district left another five people dead.
Monday's three attacks came as Iraq's top political leaders met publicly for the first time with the aim of ending a protracted crisis over forming a new government.
Iraq has been without a government for eight months after inconclusive general elections in March.
In addition to those killed, the car bomb in Karbala wounded more than 30 people, officials said.
Police said the target for the blast was a bus carrying Iranian pilgrims. The blast went off just 150m (490ft) from the shrine of the Imam Hussein, one of the holiest sites in Shia Islam.
Hours later, a suspected suicide bomber blew himself up near another shrine in the nearby city of Najaf.
Both cities, places of Shia pilgrimage, have frequently been the target of bomb attacks, most recently in July and August, says the BBC's Jim Muir in Baghdad.
The holy places draw hundreds of thousands of pilgrims from all over Iraq and from neighbouring Iran every year.
Pilgrims on the routes to the holy places have also often been attacked by bombers, who are believed to be Sunni militants.
The explosion in a busy street in Basra left at least five people dead and 37 more injured.
Basra has been comparatively free of insurgent violence this year. However, a twin car bomb attack in August left more than 40 people dead.
Last week about a dozen co-ordinated bombs targeted Shia districts across Baghdad, killing more than 60 people and wounding hundreds.
Those attacks came two days after at least 52 people were killed as police stormed a church in Baghdad where hostages were being held.
Analysts have said that the spike in violence could be a last-ditch attempt by al-Qaeda to exploit the political vacuum in the country.