The violence follows the start of the Islamic new year and as Shiite Muslims converge on the shrine city of Karbala, south of Baghdad, for commemoration ceremonies.
The bloodshed is the latest in Iraq's worst violence since 2008, with more than 5,500 people dead this year despite tightened security measures and a swathe of operations against militants.
A car bomb in the predominantly-Shiite neighbourhood of Baghdad Jadida, in the capital's east, killed at least three people and wounded nine others, police and medical officials said.
The blast comes as pilgrims take part in Ashura commemorations, due on November 14 to mark the death of Imam Hussein, grandson of the Prophet Mohammed who was killed in 680 AD by the armies of the caliph Yazid.