Chicago police are warning residents to watch their surroundings after three armed robberies were reported on the city's North Side.

The first robbery happened Monday night around 8:40 p.m. in the 2600 block of North Clark Street in Lincoln Park. 

Two more robberies happened two minutes apart, at 12:13 and 12:15 a.m. Tuesday, in the Lake View East neighborhood in the 3200 and 3400 blocks of North Broadway.

Police said in each incident, one or two suspects wearing dark clothing and ski masks approached the victims while armed with a black handgun, demanded the victim's belongings, including their cellphones, wallets, and/or purses. 

Police did not have a detailed description of the suspects, but said they may have been between 13-16 years of age.

Residents are encouraged to be aware of their surroundings, report suspicious activity, and remain on the scene and call 911 if an incident does occur.

Anyone with information is asked to contact Area 3 detectives at 312-744-8263 or submit an anonymous tip at CPDTIP.com, using reference number P253050.