A hospital official says three bomb blasts targeting Shiite pilgrims south of Baghdad have killed at least six people and wounded 40.

Dr. Radwan al-Kindi says the bombs exploded Friday on the road to Kufa, one of the main routes to the southern holy city of Najaf.

Al-Kindi, the director of the Najaf medical center, said those killed were pilgrims.

No further details were immediately available.

The blasts are the latest in a string of attacks that have killed or wounded hundreds of Shiite pilgrims in Iraq in recent weeks.