Almost two dozen children were injured when a platform collapsed at a parkour gym in San Diego on Saturday night.
The incident occurred at Vault PK in San Diego in the middle of an open gym night.
Apart from that, two adults between the ages of 46 and 72 were also injured when the 20-by-30 foot wooden deck and stairwell collapsed.
One child possibly suffered a moderate spinal cord injury due to the way he fell and a second child suffered a possible moderate head injury, the San Diego Fire Department said.
Parents at the scene said about 50 children were expected to attend the event, but more than twice as many were present.
The authorities have not yet released any official cause behind the collapse of the stairwell. Children were also running up and down the stairwell to get pizza just before the incident, another parent told the newspaper.
Joe Saari said when he and his wife dropped off their two children for a few hours there were 100 to 150 kids at the facility, a warehouse that includes trampolines and bouncy houses.
His kids suffered minor scrapes, Saari said. The couple had headed back home to Chula Vista when one of their children called and said there had been an accident. I am just as devastated for all the children affected as any other parent.
Parkour is a physical discipline in which participants attempt to get from one point to another, often involving jumping from one structure to another at obstacle course-like facilities.