Several trains on the Beijing-Guangzhou high-speed railway were delayed on Friday due to a massive water leak, railway authorities said.

The leak was discovered around noon Friday in a section of tunnel that connects the cities of Changsha and Miluo in central China's Hunan Province.

Repairs are under way.

The Beijing-Guangzhou line, the longest high-speed railway in the world, has a total length of 2,298 km and went into operation on Dec. 26, 2012.