BEIJING — Now that China had completed a 10,000-foot runway fit for fighter jets and dredged a huge harbor at Fiery Cross Reef, an artificial island at the center of a territorial dispute in the South China Sea, the time had come to reward the workers who built them.

One of China’s biggest navy ships, a type of amphibious assault vessel, arrived at Fiery Cross Reef this week loaded with a performance group from the People’s Liberation Army. They danced and sang for two and a half hours before a cheering crowd of military personnel and construction workers.

A video of the performance by CCTV, the Chinese state broadcaster, showed the gray hull of the Kunlunshan, a 20,000-ton warship and the second-largest vessel in the Chinese fleet, as the backdrop for the temporary stage rigged up portside.