Robert Tempkin told the BBC: "Everyone was screaming and running, there were coats and people's phones on the floor. People just dropped everything. Some people were screaming they'd seen blood but other people were saying it was balloons busting or a speaker had been popped. There were lots of ambulances. I saw somebody being treated. I couldn't tell what had happened to him."
Witnesses recorded the hysteria and shared it on social media.
“Just got out of Manchester arena after seeing Ariana perform. There was a loud bang when the lights came on & everyone ran out screaming," one fan wrote.
"Two loud bangs heard around Manchester arena. People running out of the arena. No idea what's going on," another wrote.
This article previously appeared on Girlfriend.