ZHUHAI - Divers on Friday went underwater to repair a leaking natural gas pipeline in the South China Sea operated by CNOOC, China's largest offshore energy explorer.

Engineers have been pumping nitrogen into the leak to replace natural gas in order to facilitate the divers' operations. No sea pollution has been reported since the leak was spotted on Monday, said Qiu Daqing, a CNOOC gas field manager.

Qiu said the divers will identify the state of the leak and take provisional measures to seal it. Engineers will then remove the damaged pipe and replace it with a new one.

The leak was detected Monday by fishermen about 12 kilometers from the natural gas terminal in the city of Zhuhai, Guangdong province, and after days of active pressure venting, the internal pressure of the pipe had been reduced to an appropriate level for repair, CNOOC officials said.