It happened near the 900 block of Tidewater Road in Pasadena around 3:10 p.m. on Saturday, March 30, the AACPD said.
Two victims were approached by a group of about seven teens, assaulted, and robbed, police said.
Officers found and charged three 13-year-olds during a follow-up search; two males from Glen Burnie and Severn, and a female from Linthicum Heights.
No weapons were displayed during the assault, police said.
The investigation is being led by Eastern District detectives. Anyone with information is asked to call 410-222-6145 or the Eastern District Tip Line at 410-222-3502.
Click here to follow Daily Voice Gaithersburg and receive free news updates.