Four Shiite pilgrims were killed and 13 others wounded by a roadside bomb explosion in eastern Baghdad on Monday, an Interior Ministry source said.
A roadside bomb struck a bus carrying Shiite pilgrims in the Obaidi district, killing four of them and wounding 13 others, the source told Xinhua on condition of anonymity
The pilgrims were returning to their homes in eastern the capital after observed the major religious ceremony of Arbaeen in the holy city of Karbala, some 110 km southwest of Baghdad.
Earlier in the day, another roadside bomb explosion hit a minibus in the Shiite district of Sadr City, killing four people and wounding 10 others.
The attacks came as the major Shiite ritual of Arbaeen reaches its climax on Monday, as hundreds of thousands of Shiite pilgrims are observing the ceremony in the holy city of Karbala.
Arbaeen is the end of 40 days of mourning for the Imam Hussein, the Prophet Muhammad's grandson who was killed at the battle of Karbala in 680 A.D.