The death toll was climbing in an explosion at a concert in the U.K. by Ariana Grande. Details are still coming in but the BBC has reported that at least 19 people are dead, with about 50 injured.

Witnesses said they heard two loud bangs just after the concert at Manchester Arena. Authorities were treating it as a possible terrorist attack.

“Network Rail said train lines out of Manchester Victoria station, which is close to the concert venue, were blocked,” the story reports. “Greater Manchester Police tweeted to urge people to stay away from the area.

Witnesses described the chaos in the immediate aftermath of the blast.

“People were just crying and in tears … police cars were everywhere,” said one witness, adding: “It was bedlam… it was horrific.”

Details are continuing to come in.