Iraq: Bomb attacks on Shia and police targets kill 50

 At least 50 people have been killed and hundreds injured in a wave of bombings and shootings across Iraq, police say.

The violence targeted predominantly Shia areas, in particular police officers and checkpoints.

In Baghdad, nine people died in two successive blasts in the central Karrada district. Outside the capital, at least two were killed in Baquba.

No group has yet said it was behind the violence. Attacks in Iraq have risen since US troops withdrew in December.

Tolls from other attacks around Baghdad include:

six dead after a car bomb in Shia-dominated Kadhimiya, north of Baghdad
six killed by gunmen at a police checkpoint in the Sarafiya district of the capital
two dead and five injured in an explosion in the western al-Mansour district
two killed and 10 injured in two explosions in Dorat Abo Sheer, southern Baghdad
two killed and nine wounded in an attack by gunmen using weapons with silencers, targeting a police patrol in Saidiya, southern Baghdad
seven injured, most of them policemen, in a blast in al-Madaen, south of Baghdad
five civilians injured in a bomb explosion in Taji, north of Baghdad

There were also attacks in Mosul, Kirkuk and the province of Salahuddin.

There are fears the death toll from Thursday's violence could rise.

A curfew is now in effect in Tikrit, the capital of Salahuddin province, and in Hilla, in Babil province, south of Baghdad.

Last week, at least 18 people were killed in a suicide attack near the Iraqi police academy in the capital.

Shia targets have come under increasing attack since the government of Shia Prime Minister Nouri al-Maliki moved against senior members of the predominantly Sunni Iraqiya political bloc.

The day after US troops withdrew, a warrant was issued for the arrest of Vice-President Tariq al-Hashemi, who is accused of financing death squads.

Mr Hashemi, who denies the charges, is currently in Iraqi Kurdistan, under the protection of the regional government. He is the most senior Sunni politician in the Iraqi government.

The BBC's Rafid Jabbouri, in Baghdad, says Shia government officials accuse people linked to Mr Hashemi of being behind recent outbreaks of violence.

Mr Hashemi appeared on TV to deny any involvement.

Al-Qaeda in Iraq said it carried out previous waves of attacks in December and January.