SEOUL, South Korea » South Korea ordered hundreds of people Tuesday to stay out of a high-rise shopping mall in Seoul that shook briefly for unknown reasons, an official said.

The 39-floor Techno Mart building in Seoul’s Gwangjin neighborhood shook for about 10 minutes, officials said.

Park Je-hyeon, a local fire official, said the evacuation order would last three days, during which experts would examine the 13-year-old building near the city’s main river.

“If defects are found, the order may be extended,” Park said.

Gwangjin fire officials said earlier that the shaking was limited to one part of the building.

About 300 office workers had earlier left and then returned to the building after the shaking. No injuries were reported.