CHICAGO (CBS) — Police are warning North Side residents of a recent increase in late night and early morning armed robberies.

Two men approach their victims on the street or in alleys and steal money, wallets and cell phones at gunpoint, according to a community alert from Area North detectives.

The robberies happened at:

1:05 a.m. July 21 in the 1500 block of West Altgeld Street,

about 1:15 a.m. July 21 in the 1500 block of West George Street;

about 11 p.m. July 27 in the 1300 block of West Grace Street;

about 4:10 a.m. July 30 in the 1200 block of West Belmont Avenue;

about 10:30 p.m. July 30 in the 4700 block of North Hermitage Avenue;

about 11:35 p.m. July 30 in the 1400 block of West Roscoe Street;

and about 10:45 p.m. Aug. 22 in the 1700 block of West Cullom Avenue, police said.

In each robbery, the robbers exit a vehicle, rob their victims and then flee in the vehicle, police said. The vehicle descriptions include a two-door Toyota, a black Chevrolet and a beige sedan.

The suspects are described as 18- to 35-year-old black men, police said. In two of the robberies, the suspect was described as having a shaved or bald head.

Anyone with information about the robbers should call Area North detectives at (312) 744-8263.

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