At least one person was killed and 16 injured Thursday in a car bombing which hit a bus carrying Shiite Muslim pilgrims in southern Iraq, said security officials, dpa reported.
The blast occurred in the southern holy city of Karbala, a day after at least 26 people, mainly Kurds, were killed in a series of bombings, they added.
The surge in attacks comes amid a crisis pitting Shiite Prime Minister Nuri al-Maliki against the country's formerly dominant Sunni minority.
Iraq's Sunnis have in recent weeks held massive demonstrations against al-Maliki, accusing him of marginalizing their politicians.
Iraq has witnessed near-daily attacks since US troops withdrew in December 2011, raising fears of a return to the sectarian tensions that drove the country close to civil war in 2006 and 2007.