Article published on the 2010-01-14 Latest update 2010-01-14 15:25 TU
Routes to Najaf, which is 150 kilometres from Baghdad, have been sealed off and large numbers of Iraqi security forces have been deployed.
The attacks came hours after an Iraqi court sentenced 11 men to death in the first trial to convict suspects for three major bomb attacks in the centre of the Iraqi capital last August.
Salim Abed Jassim was sentenced to death after he confessed to receiving funds for the attacks from Brigadier General Nabil Abdul Rahman, who was a senior army officer during Saddam Hussein's rule.
An Iraq Al-Qaeda leader, Ishaq Mohammed Abbas, and his brother Mustapha, were also sentenced.
"They are sentenced to death for the crime they planned," the president of the criminal court, Ali Abdul Sattar, told the hearing in Baghdad.
The Baghdad attacks in August killed 106 people and wounded 600 others on a day that was dubbed Black Wednesday.
The government blamed the bombings on Al-Qaeda and Saddam Hussein loyalist, but admitted that negligence at checkpoints allowed the bombers to enter the city.