A senior U.S. defense official claims that China’s latest nuclear-powered attack submarine, part of the country’s naval expansion, sank earlier this year.
The first of its kind, Zhou-class submarine docked in Wuhan, sank between May and June. Chinese officials have refused to comment on the incident, trying to keep it a secret.
The sinking of the vessel, designed with advanced technology and an X-shaped stern, might have embarrassed Beijing, which is actively...