A major US bridge has collapsed after being struck by a ship, reportedly sending people and vehicles plunging into the river below.The ship struck the Francis Scott Key Bridge in Baltimore around 1.30am on Tuesday morning.Dramatic footage of the incident shows the boat catching fire before sinking, sending multiple vehicles into the water beneath the bridge. Within 30 seconds a large section of the bridge was destroyed.The Baltimore mayor said emergency personnel were on scene and rescue efforts were underway.Chief Kevin Cartwright, director of communications for the Baltimore City Fire Department, told the BBC the bridge had been struck by "a large vessel" causing it to collapse into the Patapsco River.He added that "as many as seven individuals and several vehicles" have fallen into the river.