Baghdad (CNN) -- At least five people were killed and 30 others wounded Friday after a bombing outside a Sunni mosque in northeastern Baghdad, police said.
The blast took place as worshippers were leaving the mosque in the al-Rashidiya neighborhood following Friday prayers, police said.
There has been an uptick in violence lately between Shiites and Sunni Arabs, and the persistent tensions have stoked widespread fears that the simmering hostilities, which raged during the Iraq War, could morph into a civil war.
Since the overthrow of Saddam Hussein's government, Sunni Arabs have been politically marginalized, and Shiites, who represent a majority of Iraqis, have emerged with more power.
There have been protests for months by Sunni Arabs against the Shiite-led government and its prime minister, Nuri al-Maliki. The anger has escalated since a confrontation last week between police and protesters in Hawija.
More people died violently in Iraq in April than in any other month since June 2008, the United Nations said Thursday.
A total of 712 people died and 1,633 more sustained injuries "in acts of terrorism and acts of violence," the U.N. Assistance Mission for Iraq said. Civilians made up most of the victims -- 595 -- and 1,438 civilians were injured.