At least 16 people watching an outdoor pop concert in South Korea fell 20 metres to their deaths when a ventilation grill they were standing on collapsed.
Photos of the scene in Seongnam, just south of Seoul, showed a deep concrete shaft under the broken ventilation grill.
Eleven others are seriously injured.
The victims were standing on the grill while watching an outdoor performance by girlband 4Minute, which is popular across Asia.
About 700 people had gathered to watch the concert, which was part of a local festival.
The YTN television network said many of the spectators were female students.
A video from the scene recorded by someone at the concert that later ran on YTN showed the band continuing to dance for a while in front of a crowd that appeared to be unaware of the accident.
Meanwhile, dozens of people were shown standing next to the ventilation grill, gazing into the dark gaping hole where people had been standing on the grill to watch the performance. YTN said the ventilation grill was about three to four meters wide. Photos apparently taken at the scene showed that the ventilation grill reached to the shoulders of many passers-by.
The cause of the accident is not yet known.