An investigation is under way to discover how grandstand seating collapsed during a prayer session at a religious festival in Lincolnshire.
Four people were seriously injured in the accident at Grapevine Christian Festival near Lincoln on Sunday.
A small section of the grandstand gave way and more than a dozen people suffered minor injuries.
Grapevine spokesman Brian Keel said: "We don't know what caused it to collapse, it just gave way."
He added: "People were involved in worship when it was happening.
"There was a senior police officer in the venue and he took control in less than a minute. He took over the evacuation of the marquee so the affected areas were evacuated first.
A police spokesman said: "It would seem there is nobody with life-threatening injuries as far as we can tell."
The 5,000-capacity marquee was close to full when the incident happened.
Insp Dick Holmes of Lincolnshire Police said: "All credit to the organisers who had a contingency
plan for something like this. There was no panic, and it looks like it could have been a lot worse."
He said the Health and Safety Executive would launch an investigation.
A hotline has been set up for people who are worried about
friends and family who attended the festival.