Baghdad (CNN) -- The death toll from a suicide bombing onboard a bus carrying Shiite pilgrims in Iraq rose to 50 on Sunday, police said.
Saturday's attack -- which occurred between Baghdad and Samarra -- also wounded 82 people, and was the second targeting pilgrims in three days.
The suicide bomber detonated at least 10 kilograms of explosives concealed in his vest when he stepped into the bus, Samarra police officials said.
Most of the casualties were Shiite pilgrims heading back south to Nasiriya from Samarra in the north. Some of the wounded were on other buses waiting at the security checkpoint where the attack occurred.
The pilgrims had journeyed 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.