BAGHDAD — A series of attacks on Sunday against markets, shopping areas and auto repair shops in largely Shiite neighborhoods of Baghdad killed at least 45 people and wounded dozens more, the police and medical officials said.

Iraq is experiencing a protracted wave of sectarian violence that has increased since the American military withdrawal in 2011, a level of strife not seen since 2006 and 2007. More than 8,000 Iraqis have been killed so far this year, according to the United Nations.

The first bombing on Sunday hit the Amil neighborhood in western Baghdad around 7:30 a.m. in a crowded shopping district near a bus stop, killing at least six and wounding 19 others.

Later, a car bomb exploded on a street filled with factories and car repair shops in Baya, a neighborhood in southwestern Baghdad, killing seven people and wounding 20, the police said.