A suicide bomber blew himself up outside a college campus in eastern Baghdad on Sunday, killing 40 people and wounding 35 others, an interior ministry source said.
"The death toll climbed to 40 people killed and 35 others wounded and most of them were students," the source told on condition of anonymity.
Meanwhile, a series of car bombs and mortar attacks rocked Baghdad despite a major offensive launched by the US and Iraqi forces aimed at curbing violence.
On Sunday morning, a car bomb parked some 100 meters away from the Iranian embassy near the Green Zone in central Baghdad detonated, killing two civilians and wounding four others, the police said.
Another car bomb went off near the Jabbar Abu al-Sharbat soft drink store in the Karradah neighbourhood in central Baghdad, wounding four people. The explosion sent a plume of black smoke into the air.
Central Baghdad also witnessed a mortar attack, which wounded three people in the Elwiyah neighbourhood, according to the source.
Earlier, rockets hit the Abu Dshier neighbourhood in southern Baghdad, wounding two people, he added.