Chinese government hackers have been accused of stealing sensitive data from the computers of a US Navy contractor, including plans for submarine-launched supersonic anti-ship missiles

The breaches took place in January and February, US officials told the Washington Post, speaking on condition of anonymity about an ongoing investigation led by the Navy and assisted by the Federal Bureau of Investigation.

The US Navy declined to comment other than to say: "Per federal regulations, there are measures in place that require companies to notify the government when a 'cyber incident' has occurred that has actual or potential adverse effects on their networks that contain controlled unclassified information. It would be inappropriate to discuss further details at this time."

A spokesman for the Chinese Embassy in Washington said officials knew nothing about the reported hacking, according to Reuters, adding that the Chinese government "staunchly upholds cyber security, firmly opposes and combats all forms of cyber attacks in accordance with law".

The hackers are believed to have targeted a contractor working for the Naval Undersea Warfare Centre, on Rhode Island.