Satellite images show that the last of China’s nuclear-powered attack submarines sank several months ago alongside a pier while under construction, a senior US defence official said.

China’s first Zhou-class submarine likely sank between May and June, when satellite images showed cranes needed to lift it from the riverbed, said the official, who spoke on condition of anonymity.

It is not clear what led to the sinking of it, not even if it was loaded with nuclear fuel. China already has the world’s largest warship fleet, with more than 370 ships, and has begun production of a new generation of nuclear-powered submarines, which worries the US.

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Beijing has not acknowledged the sinking, and the official said it was “no surprise” that China’s navy would cover it up. The submarine’s current status is unknown, but the development is believed to potentially embarrass Beijing as it seeks to expand its military capabilities.

China’s embassy in Washington did not respond to a request for comment. The news was first reported by the Wall Street Journal. Satellite images from Planet Labs taken in June show cranes at the Wuchang shipyard where the submarine is supposed to be docked.

In 2022, China possessed six nuclear-powered ballistic missile submarines, six nuclear-powered attack submarines, and 48 conventional attack submarines, according to a Pentagon report on Beijing’s military capabilities. 

The submarine force is expected to grow to 65 by 2025 and 80 by 2035, the US Department of Defence estimates.

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