Police advised the public to avoid the area around the Manchester Arena, and the train station near the arena, Victoria Station, was evacuated and all trains canceled.
Joseph Carozza, a representative from Grande's U.S. record label, said the singer is OK and they are investigating what happened.
. "It was one bang and essentially everyone from the other side of the arena where the bang was heard from suddenly came running towards us as they were trying to exit."
Added Oliver Jones, 17: "The bang echoed around the foyer of the arena and people started to run."
Video from inside the arena showed concertgoers screaming as the made.
