CHICAGO (CBS) — Four people were killed and at least 28 others have been wounded in shootings across the city over Labor Day weekend, according to Chicago Police.

The most recent fatal shooting happened about 10:30 p.m. Sunday in the South Shore neighborhood.

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The 17-year-old boy was standing outside in the 7800 block of South Cornell when two males walked up and opened fire. He was shot in the back and taken to Northwestern Memorial Hospital, where he was pronounced dead, police said. The Cook County medical examiner’s office has not yet confirmed the fatality.

Earlier Sunday evening, a man was shot to death in the Back of the Yards neighborhood on the South Side.

Officers responding at 6:07 p.m. to a call of a person shot in the 5200 block of South Sangamon found the 19-year-old man suffering from multiple gunshot wounds to the body. He was taken to Stroger Hospital, where he was pronounced dead, authorities said. His name has not been released.

About an hour earlier, one man was killed and another was wounded in a South Side Englewood neighborhood shooting.

The two men, 27 and 45, were unloading boxes in an alley about 5:15 p.m. in the 6700 block of South Green when someone dressed in black walked up and fired shots, police said. The 45-year-old suffered multiple gunshot wounds to the torso and chest, while the younger man was shot in the chest, back and wrist. They were both taken to Christ Medical Center in Oak Lawn, where the older man, whose name has not been released, was pronounced dead, police said. The 27-year-old man was listed in serious condition.

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The holiday weekend’s first fatal shooting happened early Sunday in the Archer Heights neighborhood on the Southwest Side.

Juan Pita-Rosas, 32, was standing in an alley with a 22-year-old man about 12:10 a.m. in the 4800 block of South Kildare when they heard gunfire and both felt pain, according to police and the medical examiner’s office. Pita-Rosas, who lived in the 4700 block of South Springfield, was shot in the head and taken to Mount Sinai Hospital, where he was pronounced dead at 1:05 a.m. The younger man suffered gunshot wounds to the arm and chest and later showed up at Holy Cross Hospital, where he was listed in serious condition.

The most recent nonfatal shooting happened shortly before 1 a.m. Monday in the Fernwood neighborhood on the Far South Side.

Two men, 18 and 19, were sitting in the back of a vehicle parked in the 10100 block of South Princeton when another male walked up and opened fire, police said. The 18-year-old suffered gunshot wounds to the back, torso and left leg, while the older man was shot in the right leg. They were both taken to Christ Medical Center, where their conditions were stabilized.

At least 24 more people have been shot in Chicago since 9 p.m. Friday. Last year, 54 people were shot—8 fatally—over Labor Day weekend.

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(Source: Sun-Times Media Wire © Chicago Sun-Times 2016. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed.)