Medics transported both victims from the scene near Fond du Lac and West Hampton avenues shortly before noon, according to the Milwaukee Police Department. Police described their injuries as nonfatal.

A transit spokesperson confirmed that gunfire broke out on a Route 11 bus. The driver and three other passengers aboard were not injured, the spokesperson said, and the transit system is cooperating with the police investigation.

Investigators have not publicly described what led up to the shooting or identified a suspect. Police said the circumstances remain under investigation and asked anyone with information to call 414-935-7360. Tipsters who wish to remain anonymous can contact Crime Stoppers at 414-224-TIPS or submit information through the P3 Tips app.

The shooting adds to a string of violent incidents that have unsettled riders and workers on Milwaukee's bus network in recent years, prompting repeated calls from transit advocates and union representatives for stronger safety measures aboard buses and at busy transfer points. Route 11 runs along Fond du Lac Avenue, a corridor that serves thousands of daily riders and connects some of the city's most heavily traveled north-side neighborhoods.

Tuesday's gunfire occurred in daylight on a busy stretch of the route, a detail that community safety advocates say underscores the need for reliable, well-staffed transit service that riders can use without fear. County officials have not said whether additional security measures will be added to the route in the wake of the shooting.

Police have not released the names of the victims or said whether they knew each other. Anyone who witnessed the incident or has information about the shooting is urged to come forward.