An injured concertgoer is escorted from the Arena.

Helpers attend to injured people inside the arena. Picture: PA via AP

Concert goers wait to be picked up at the scene of a suspected terrorist attack during a pop concert by US star Ariana Grande. Picture: AFP

Police escort members of the public from the Manchester Arena. Most of the fans were young girls, as Caroline Overington writes. Picture: Getty Images

A blast caused panic inside the Manchester Arena as an Ariana Grande concert came to an end. Picture: Twitter/@hannawwh

Ariana Grande, a 23-year-old American pop star, is enormously popular with young girls and has an enormous following on Instagram. Picture: AP

Police with sniffer dogs inspect the scene of the suspected terrorist attack. Picture: AFP

Scores of young teenagers who were attending the concert, and who have been separated from their parents, have been taken in by hotels nearby the concert venue. Picture: AP

Police and fans close to the Manchester Arena. Picture: Getty Images

Police stand by a cordoned off street close to the Manchester Arena, the largest indoor arena in Europe with a capacity for 21,000 people.

Dazed young fans leave the area after the explosion hit. Picture: Getty Images

Greater Manchester Police have confirmed there are fatalities and warned people to stay away from the area. Picture: Getty Images

Armed police respond after reports of the explosion.

Emergency services arrive close to the Manchester Arena to assist the injured. Picture: Getty Images

Police speak to fans who have fled the Manchester Arena. Picture: Getty Images

Medicos are deployed to assist. Authorities report there are 19 fatalities and as many as 50 further casualties. Picture: AFP

Members of the public receive treatment from emergency service staff at Victoria Railway Station close to the Manchester Arena. Picture: Getty Images Live updates to the Manchester Arena story here.

A sign is left in the street after the explosion. Picture: Getty