Brent Sadler, a former submarine officer at Washington’s Heritage Foundation think tank, said: “The sinking of a new nuclear sub that was produced at a new yard will slow China’s plans to grow its nuclear submarine fleet. This is significant.”

Undersea warfare has become a Chinese priority in its arms race with the US as tensions rise in the Pacific.

Submarines would probably play a key role in any future conflict over Taiwan, with a Chinese fleet potentially attempting to invade, while blockading the US from arming and supplying the island.

Submarine warfare has traditionally been an area of significant US supremacy, but China’s People’s Liberation Army (PLA) navy has been closing the gap.

A senior US defence official told The Wall Street Journal: “It’s not surprising that the PLA Navy would try to conceal the fact that their new first-in-class nuclear-powered attack submarine sank pierside.

“In addition to the obvious questions about training standards and equipment quality, the incident raises deeper questions about the PLA’s internal accountability and oversight of China’s defence industry, which has long been plagued by corruption.”