At least 67 people were killed and many others injured in car bombings in the Iraqi holy cities of Karbala and Najaf on Sunday, according to reports.

In Najaf, a suicide car bomber rammed his vehicle into a funeral procession and exploded it just yards from the Imam Ali shrine, killing at least 51 people.

CNN quoted Najaf police chief Ghalib Jazairi as saying that an Iraqi suspected of being involved in the attack was arrested.

The suspect was picked up trying to escape the city in a car full of explosives, Jazairi said.

The Karbala attack, which took place near the Bab Baghdad bus station -- killed 16 people and wounded 37.

One of Najaf's leading Shia clerics, Grand Ayatollah Mohammed Said al-Hakim, denounced the bombings.

He said they aimed to "incite sectarian sedition" and that god would "avenge and compensate" the victims.