A bomb has ripped through a wedding convoy in Baghdad, killing at least 15 people, four of them children, the interior ministry says.
A bus with wedding guests was among the targets
The car bomb struck a procession of vehicles at dusk in Ur, on the outskirts of Baghdad's Sadr City.
The bomb came as residents of Sadr City celebrated the lifting of a security cordon around the Shia stronghold.
The blockade was imposed after the authorities suspected that an abducted American soldier might be held there.
At total of at least 19 people were injured in the attack on the wedding party.
Earlier, at least 30 bus passengers were kidnapped by an armed gang on a road north of Baghdad, police say.
An official said the bus, carrying mainly Shia passengers to the town of Balad, was stopped at a fake checkpoint 40km (24 miles) from the capital.
It is the latest in a spate of mass kidnappings, part of the growing sectarian violence in Iraq.
According to police, the bus attack occurred when gunmen stopped the vehicle on its way to the northern town of Balad, the scene of bitter sectarian tensions recently.
Two weeks ago, at least 30 Sunnis were killed by a Shia militia there in an apparent revenge attack for the murder of 17 Shias.
The two attacks came as Iraqi Prime Minister Nouri Maliki ordered all checkpoints around the Shia suburb of Sadr City to be lifted.
US and Iraqi forces began lifting the blockade shortly ahead of a deadline imposed by Mr Maliki.
Residents of the Shia district celebrated as the Iraqi troops removed coils of barbed wire and red traffic cones from the streets of the sprawling district.
US forces had erected a security cordon around the area as they carried out searches for an abducted soldier.
The week-long restrictions, checks and searches caused increasing resentment in the densely-populated neighbourhood.
The decision to lift them came shortly after radical Shia cleric, Moqtada Sadr, called a general strike in protest.
The district is largely controlled by the Mehdi Army, a militia led by Mr Sadr.
The area has seen brief clashes between US forces and the Mehdi Army since the blockade was imposed.
The BBC's regional analyst, Roger Hardy, says the Iraqi prime minister's announcement reveals the increasing tension between the Baghdad government and the US administration.
He says they are at odds over security issues, what to do about militias, and how best to achieve national reconciliation - especially with the country's aggrieved Sunni Arab minority.
The abducted man, an Iraq-born US serviceman was seized last Monday after leaving his base inside Baghdad's fortified Green Zone to visit Iraqi relatives in the city.