At least 30 people were killed and 42 injured Sunday when a suicide bomber wearing an explosive vest attacked a mosque south of Baghdad, according to police and health officials.
The mosque is located in al-Musayab, about 70 kilometers (43 miles) south of the capital.
The attack targeted Shiite mourners, who were at the mosque for a funeral.
Iraq has seen a sharp increase in tension between its Shiite and Sunni populations since April, when security forces raided a site used by Sunni protesters to demonstrate against the Shiite-led government.
Sunnis, who represent a minority of Iraqis, have felt politically marginalized since the overthrow of Saddam Hussein in 2003. Shiites, who make up a majority of Iraqis, now dominate the government.
In a separate incident Sunday, at least 12 people were killed in an attack on the security headquarters of the regional Kurdish government in Erbil.
A suicide bomber in a minibus attempted to enter the facility. Kurdish security forces opened fire, and the vehicle exploded.
At the same time, gunmen opened fire and attempted to storm the headquarters, according to a statement from the Kurdistan Regional Government.
Of the 12 people killed, six were "terrorists" and six were members of the security forces, it said. More than 40 people were injured.