At least four people were killed and scores were injured after gunmen opened fire on a crowd in Birmingham in the US State of Alabama.According to local police, multiple gunmen shot at a crowd near Magnolia Avenue in Birmingham's Five Points South area late last night.Two men and a woman were found dead at the scene. A fourth victim succumbed to gunshot wounds in hospital.Birmingham Police Officer Truman Fitzgerald said the shooting left up to 21 people wounded, at least four of them had "life-threatening" injuries.No suspects were in custody as of early Sunday, Fitzgerald added.The incident in Alabama extends the list of at least 403 mass shootings in the United States so far this year, according to the Gun Violence Archive.Source: Qatar News Agency