Swarms of emergency services at Manchesters MEN Arena and Piccadilly Station after an explosion, March 23, 2017. [Photo/VCG]

Eyewitness Andy Holey, waiting to pick up his wife and daughter, said: "As I was waiting, an explosion went off and it threw me about 30 feet from one set of doors to the other set of doors.

"When I got up I saw bodies lying on the ground. My first thought was to go into the arena to try to find my family.

"It was definitely an explosion and it was some force. It happened near the box office at the entrance to the arena."

Manchester Arena can hold up to 18,000 people. It is regularly used to stage concerts and Grande, a 23-year-old reality TV star, is part way through a UK tour. Her management said she was not injured in the blast, which came just after she finished her last song.

She sent out a message on Twitter to say she was "broken" by the blast and the deaths. "I have no words," she said.

Her fans are mainly young teen and pre-teenage girls, many of whom were at last night's concert.

Pictures on social media and news websites showed teenage girls, some wrapped in blankets, others bloodied and bandaged, being helped by emergency medical teams.

Police closed off central Manchester and the main railway station, near the arena, was closed and train services suspended.

To contact the reporter: chris@mail.chinadailyuk.com