Senior US defense officials reported on Thursday that a Chinese nuclear-powered submarine sank earlier this year during its construction, in what could be a significant setback for China's naval ambitions. The Zhou-class attack submarine reportedly went down at the Wuchang shipyard between May and June.

Satellite images from June showed cranes at the shipyard where the submarine was docked, indicating a possible sinking. The Wall Street Journal first reported the incident, with confirmations from US officials speaking to various news agencies, including Reuters and the Associated Press.

China has not officially confirmed the status of the submarine. A spokesperson for the Chinese embassy in Washington stated, "We are not familiar with the situation you mentioned and currently have no information to provide."

One US official, who requested anonymity, remarked that it was "not surprising" China’s navy had kept the incident under wraps. They raised concerns over the People’s Liberation Army's (PLA) internal accountability and oversight, referencing longstanding issues of corruption within China's defense industry.

The incident could have broader implications for China's naval expansion as it seeks to bolster its military capabilities in the Asia-Pacific region.