"The latest report said that nine people were killed and 90 others wounded in four bomb attacks of Karbala," said a source from the city police, citing reports from Karbala's health office.

The first blast occurred at about 9:30 a.m. (0630 GMT) when a bomb attached to a car parking outside the passport and identity card office in central Karbala, some 110 km south of Baghdad, detonated, the source said.

Minutes later, a second blast ripped through the scene of the first blast, the source added.

Two blasts in a quick succession followed after about 20 minutes when Iraqi security forces spread at the scene of the earlier two blasts, he said.

Many Iraqi soldiers and policemen were among the victims, the source said, adding that some of the wounded people left the hospitals after they received treatment.

Iraqi security forces sealed off the scene and blocked all the roads leading to the heavily populated area in central the city which also includes Karbala's provincial council and the provincial police headquarters, the source said.

The attackers apparently followed old tactic which depends on creating an initial explosion to attract security forces and people, then they set off another blast to get heavier casualties, the source added.

Earlier, an Interior Ministry source said that three explosions ripped through central Karbala and killed at least five and wounded more than 20 others.

Sporadic attacks are still common in Iraqi cities despite the dramatic decrease of violence over the past few years.