On the afternoon of Dec. 20, unknown militants in south Lebanon attacked Israel, launching three rocket shells into Israeli territory. The Israeli side returned fire, launching eight rounds and seven mortar shells into Lebanese territory.

The construction engineering unit of China's first peacekeeping force in Lebanon was only five kilometers away from the "blue line" temporary boundary. Hearing the bombs whistle above their heads, the Chinese military engineers adopted elusion tactics at once. From 7 p.m. on Dec. 20 to the early hours of Dec. 21, they stayed hidden in the underground bunker.