SEOUL, Oct 17 (Reuters) - Sixteen people were killed at an open-air pop concert in South Korea on Friday when the cover of a ventilation shaft they were standing on gave way, officials and media said.

It was the latest in a string of accidents in South Korea, including the sinking of a ferry in April in which more than 300 people were killed, that has raised questions about safety and put pressure on authorities to tighten up standards.

About 27 people at the K-Pop concert fell more than 10 meters (32 feet) into the ventilation system when the cover they were standing on to get a better view of the stage gave way, Yonhap news agency and YTN television said.

Eleven people were injured, many of them seriously, a government official in Pangyo district, just south of the capital Seoul, said.

About 700 people were at the concert near a shopping mall where the group 4Minute was performing. The group features the singer and dancer Hyuna, who shot to fame after performing in the "Gangnam Style" music video by the South Korean rapper Psy.

South Korea, Asia's fourth-largest economy and one of its leading manufacturing and export powerhouses, has developed into one of the world's most technically advanced countries, but faces criticism that regulatory controls have not kept pace. (Reporting by Ju-min Park and Reuters TV; Writing by Jack Kim; Editing by Janet Lawrence)