Sixteen concert-goers are being reported dead at the Pangyo Techno Valley Festival in Seongnam, South Korea.

According to reports by media outlets around the world, including CNN, BBC, and The Guardian, a ventilation window collapsed on site during an outdoor performance by K-Pop girl group 4Minute.

After initial reports indicating that two people had died and ten were injured, the latest reports mark the death toll at sixteen with eleven others injured, eight critically.

"Twelve people were killed at the scene, two others were killed while they were being rushed to the hospital," a local fire official was quoted as saying by Korean media outlet Yonhap News.

"Others are assumed to have passed away while receiving medical treatment."

According to reports, on Friday, at approximately 5 p.m. Korean Standard Time, more than 25 fans fell roughly three stories onto a parking structure after the vent collapsed.

Meanwhile, the YTN television network reported that many of the spectators were young female students, as reported by several unidentified witnesses.

Officials at the scene have suggested the incident may have been caused by the weight of the fans who had climbed on top of the structure to watch the performance.

About 700 people had reportedly gathered to watch the concert.

The accident is intensifying concerns about safetly measures in South Korea, which has been a matter of much debate since the Sewol Ferry tragedy that took the lives of more than 300 people, most of whom were high school students on a class field trip.  Many have suggested that the rapid rate in which South Korea has developed has led to lax security standards resulting in such tragedies.

Cube Entertainment, 4Minute's record label and management company, has issued a statement that they are looking into the matter and will release a statement soon.