Four workers were trapped five meters underground after scaffolding collapsed at a reservoir construction site in eastern South Korea, police officials said Thursday.

   Police and firefighters are trying to find the best approach to rescue them, but rescue efforts were complicated by huge amounts of debris, officials said. Two other construction workers near the site of the collapse were injured and sent to a nearby hospital.

   The accident happened around 4:30 p.m. at the construction site to build a 50-meter-wide, 7-meter-high waterway for a reservoir near the eastern port city of Gangneung, 237 kilometers east of Seoul.

   The identifications of the trapped workers were not immediately available, and police are investigating the exact cause of the accident, officials said.

(Yonhap News)