SEOUL, South Korea >> A news report says the shaking at a South Korean high-rise shopping mall that forced the evacuation of hundreds of people was likely caused by people jumping in a fitness center.

Yonhap news agency reported Tuesday that inspectors reached that conclusion after finding similar shaking occurred when they had a group of people perform test jumps together at the mall’s fitness center.

Yonhap cited Dankook University professor Chung Lan, who took part in the safety checks of the 39-floor Techno Mart building in Seoul’s Gwangjin neighborhood.

The building shook for about 10 minutes earlier this month though no injuries were reported.

Techno Mart officials couldn’t immediately confirm the Yonhap report.