Several people were taken to the hospital after a “female offender” opened fire with a BB gun Wednesday in a North Side Starbucks, Chicago police said.

Officers responded to a “mental health disturbance” in the 5300 block of North Clark Street about 3:23 p.m. in the Andersonville neighborhood, police said. Police said the female fired shots from a “pellet gun” but were not immediately certain anyone was injured.

Police later said “several victims” were struck and taken to St. Francis Hospital in nearby Evanston.

Reached by phone, a spokesperson for Seattle-based coffee chain said they would continue to work with law enforcement and the company's primary concern was with the injured.

“We are grateful that our partners acted quickly to help the injured customers and notify law enforcement,” they said.

Rich McMurray was in the coffee shop when the pellets began to fly.

“We heard a noise and everyone was kind of looking around,” he said. “I saw a couple people holding their neck—and everyone was just kind of shocked, it seemed like, and wasn’t really sure what happened.”

McMurray said he thought the sound might have been a Taser but didn’t have the “zap noise.”

He said he was told several people were shot with the BB gun in the store and at least one person was shot outside on the street.

“Somebody on the street looked like there was some blood on his face,” he said.

Police, fire trucks and ambulances, "the whole deal," showed up on the scene, McMurray said.

“To hear someone was randomly shooting people with a pellet gun was a bit strange—especially here,” he said.

Jim Winters had just gotten to the coffee shop and said he was sitting just two feet away from the woman he says stood up and opened fire with the pellet gun “about three times.”

“Nobody really quite new what happened at first, it sounded like firecrackers or something like that,” he said.

According to Winters, at least two people were shot in the neck by the woman wielding the BB gun.

“Pretty badly … not seriously badly, but they were bleeding quite a bit,” he said.

Winters said the woman was apprehended by police within 30 minutes after she left the store.

“It was really strange—it was bizarre—it was surreal,” he said. “This side of the coffee shop (where the shooting happened) was up for grabs and that part was kind of like business as usual.”

It was unclear if the woman would face any criminal charges.

“It was in between a very serious thing and something that you could tell wasn’t as serious as it could have been,” Winters said. “You don’t see it every day—no, no you don’t.”