(CNN) -- A suicide bomber blew himself up amid a crowd of worshipers at a Shiite mosque in Baghdad on Wednesday, killing at least 30 people and wounding 55, police said.
The bomber wore an explosive vest, which he detonated Wednesday evening in the northwestern al-Kassra neighborhood, police officials said. The force of the blast damaged not only the mosque but several buildings nearby, police said.
Initial reports indicated that the bomber targeted worshipers outside the mosque, but later reports suggested that the blast took place inside. Another man wearing a suicide vest was arrested nearby, apparently planning to attack police when they arrived at the scene, police said.
Iraq has seen a sharp increase in friction between its Shiite and Sunni populations since April, when Iraqi security forces raided a site used by Sunni protesters to demonstrate against the Shiite-led government. Sunnis have felt politically marginalized under Shiite President Nuri al-Maliki, whose government fears that Sunni Islamists involved in fighting in neighboring Syria are now targeting it.
More than 800 Iraqis were killed and another 2,030 wounded in violence and acts of terrorism in August, the United Nations said.