Gunshots rang out at a Madison, Wisconsin apartment building on Sunday, leaving at least 10 people — including a teenager — injured, police said. 

Officers were responding to a rooftop party at the Lux apartments around 12:45 a.m. when dispatch alerted them of a shooting, officials said. Dozens of people were trying to run from the building as they arrived. A teen with multiple gunshot wounds was bleeding in the street, Police Chief Shon Barnes said during a press conference, according to CBS News affiliate WISC. 

“Officers were notified that there were likely more victims in the building,” Barnes said during the press conference. “As a result, Madison police officers bravely ran up 12 flights of stairs to reach the rooftop, unaware of what they may encounter. They found some people in various stages of distress, and some were even hiding in a maintenance closet in an attempt to find safety.”

He said it was a miracle that no one had died. The victims range in age from 14 to 23, officials said. Not all of the injuries were from gunshot wounds, but the local fire department said it had taken five victims with gunshot wounds to the hospital. 

Some of the injured made their way to the hospital themselves. Police said none of the injuries are believed to be life-threatening.

Police said the shooting appeared to be a targeted incident. Officers have not yet made any arrests. Officials also have not released a description of the shooter. Detectives are still talking with victims and witnesses and looking over digital evidence, authorities said.