China has been caught trying to cover up an embarrassing blunder after its newest nuclear-powered submarine sank into the harbour while under construction. Beijing officials spent months attempting to hide the accident, until it was finally discovered by US satellite photography.

China's newest nuclear-powered attack submarine sank earlier this year, a senior U.S. defense official said on Thursday, a potential embarrassment for Beijing as it seeks to expand its military capabilities.

A U.S. officials says China's newest nuclear-powered submarine in its fleet sank in spring while docked at a pier but Chinese government officials have taken steps to cover it up.

A Chinese nuclear-powered attack submarine sank in its dock earlier this year while under construction, in a major setback for the Chinese military, according to US defence officials. Speaking on condition of anonymity to the BBC's US partner,

Building a potent nuclear submarine force would help China tighten control over its peripheral waters and improve its ability to seize Taiwan.