Manchester explosion: 'Suicide bomber suspected' after 19 people die at Ariana Grande concert

Police said they believe a suicide bomber may have been responsible for the deadly incident in Manchester that left at least 19 people, according to US officials reportedly briefed on what happened.

More than 50 people were also injured in the incident that took place at the conclusion of a concert by US singer, Ariana Grande, and which police said they were treating it as a suspected terrorist attack. Police carried out a controlled explosion on a suspect device several hours after the blast but subsequently revealed it had been a harmless bag.

Prime Minister Theresa May paid tribute to the victims and families of those involved in “what is being treated by the police as an appalling terrorist attack”.

If confirmed as a terrorism incident, it would be the deadliest attack in Britain by militants since four young British Muslims killed 52 people in suicide bombings on London's transport system in July 2005. Reuters said US officials had been told police in Manchester suspected a suicide bomber carried out the attack.

Police said they responded to reports of an explosion shortly after 10.35pm at the arena, which has a capacity for 21,000 people, and where the US singer had been performing to an audience that included many children.

A witness who attended the concert said she felt a huge blast as she was leaving the arena, followed by screaming and a rush by thousands of people trying to escape the building. A video posted on Twitter showed fans, many of them young, running from the venue.

“We were making our way out and when we were right by the door there was a massive explosion and everybody was screaming,” concert-goer Catherine Macfarlane told Reuters.

“It was a huge explosion - you could feel it in your chest. It was chaotic. Everybody was running and screaming and just trying to get out.”

A spokesman for Ariana Grande, 23, said the singer was “okay”.

Manchester Arena, the largest indoor arena in Europe, opened in 1995 and is a popular concert and sporting venue.

Britain is on its second-highest alert level of “severe” meaning an attack by militants is considered highly likely.