A roadside bomb in Baghdad killed four people on a passenger bus and wounded 10 others today, Iraqi police said.
The bomb exploded in the northeast of the capital in the sprawling slum of Sadr City, a stronghold of supporters of anti-American Shia Muslim cleric Moqtada al-Sadr.
The area was relatively empty today as many Iraqi Shias have travelled to the holy city of Kerbala, 80km south of Baghdad, for one of Shia Islam's most holy rituals, Arbain.
Arbain marks the end of a mourning period for the death in a seventh century battle of Hussein, the Prophet Mohammad's grandson.
Police said they did not believe the victims targeted in the bombing were pilgrims returning from Kerbala.
Violence has fallen sharply across Iraq after years of sectarian warfare and resistance to the 2003 US-led invasion, but suicide and car bomb attacks remain common.
Reuters