Iraq suicide bombing kills at least 32

Baghdad (CNN) -- At least 32 people were killed and 28 others wounded Saturday when a suicide bomber stepped onto a bus carrying Shiite pilgrims in Iraq and detonated himself, police and interior ministry officials said.

The attack -- which occurred between Baghdad and Samarra -- was the second targeting pilgrims in the last three days. Most of the casualties were Shiite pilgrims heading back south to Nasiriya from Samarra in the north.

They made the trip to commemorate the death of Imam al-Askri, who died in 874 A.D and is buried at a Samarra mosque.

On Thursday, a suicide bomber drove into a rest tent for Shiite pilgrims north of Baghdad, killing eight people and injuring 30 others, police said.