A suicide bomber blew himself up in a bus in eastern Baghdad on Wednesday, killing four people and wounding seven others, an Interior Ministry source told Xinhua.

"A suicide bomber wearing an explosive-vest detonated himself inside a bus around midday near the Tahdeeb police station near Sadr City neighborhood," the source said on condition of anonymity.

The blast killed four passengers and wounded seven others, the source added.

Earlier, mortar rounds struck a busy central Baghdad Square of Maidan, killing eight people and wounding 40 others.

Source: Xinhua