ST. LOUIS – A gunman shot a man who allegedly attacked him Monday afternoon on a Metro Bus in north St. Louis, police say.

The shooting happened while both were riding on the bus in the 4700 block of West Florissant Avenue in the Mark Twain neighborhood.

Police responded to the situation in the 5400 block of North Kingshighway around 1:30 p.m. Both men departed the bus as officers arrived.

Investigators say the man who was shot had physically attacked the alleged gunman moments before the shooting. During the attack, the alleged gunman pulled out his weapon and shot the other man.

Both men were sent to a hospital for treatment after the incident. The alleged gunman was 48 years old. The man shot was 36 years old. No one else was hurt from the situation.

The St. Louis Metropolitan Police Department is investigating the shooting, though have not yet disclosed whether there were arrests or criminal charges in the case. FOX 2 will update as more information becomes available.