Observers said Washington has "not demonstrated adequate sincerity" on calls to restart stalled Sino-US working-level talks on cybersecurity as sensational accusations against China continue to pour in.

The comments came on Thursday as Beijing criticized a US media report that accused China of cyberespionage against Washington.

Washington has hit Beijing in the past few months with a series of accusations, including one from the US Department of Justice in mid-May against five Chinese military personnel regarding their so-called spying on business secrets.