BAGHDAD — A wave of attacks in Shiite neighborhoods in Baghdad killed at least 21 people and wounded 125 on Sunday, a security official said.

Four car bombs exploded in a market, a bus station and on a major road in the Sadr City district, killing seven people and wounding more than 30 others, officials said.

More people were killed and dozens were wounded when car bombs were set off in a market in Husseiniya, northeast of Baghdad; in the southeastern Baghdad neighborhood of Al Ameen; and in the Kamaliya area in Baghdad’s eastern suburbs.

In the central Baghdad neighborhood of Karada, near the Babil Hotel, a roadside bomb killed one person and wounded five others.