The guitarist of Alexisonfire says an accident at their Vancouver concert that injured 19 fans was "surreal."

The popular Canadian band was only 20 seconds into its first song at a free show at LiveCity Yaletown in David Lam Park Tuesday night when a mass of spectators rushed forward, causing a large barricade near the stage to collapse and hurling people to the ground.

"There was just nothing but piles and piles of kids," Dallas Green told CTV News.

Witnesses told CTV News they saw around 30 to 40 people fall to the ground on top of each other.

The band immediately stopped playing when the barrier went down and rushed to help the injured. Green himself threw down his guitar down and jumped into the crowd.

"We started trying to get everyone to calmly move back," he said.

Green said one young concertgoer was crying when he approached her.

"She told me she couldn't feel her feet. So I carried her into the medical tent and stayed with them until she could be looked after."

Nine people were sent to hospital with injuries. Two visitors suffered lower leg fractures and another reported an injured knee. Another 10 were treated and assessed at the scene by emergency medical personnel and later released.

In Pictures: Alexisonfire concert accident

On Wednesday, Live Nation president called the incident "unprecedented," saying the company has used similar barriers at concerts for more than 20 years.

"We're going to replace the barricade and investigate if that surge or that that situation doesn't manifest itself again," Paul Haagenson told CTV News.

There were approximately 7,600 people inside the concert venue at the time.

Green said the crowd appeared rambunctious because Canada had just won the men's hockey game but there were no indications of any safety concerns at the venue.

He said the band is quite upset.

"We came here to put on a good show and be part of a historic Olympics and it's been sort of overshadowed by grief and kids in the hospital."

Penny Ballem, Vancouver's City Manager, praised the band for making sure the situation didn't escalate.

"The city feels extremely confident and basically very appreciative of the band who were superb in terms of keeping the crowd aware, moving them back, and then quietly asking them to exit the site," she said.

The barrier has now been replaced. All scheduled events at the 2010 Olympic concert venue are expected to continue as planned.