After being wary of the US warship passing by the Spratlys, the Chinese navy is doing its share by making Japan wary of their naval vessel in the East China sea, particularly near the islets that are being disputed by Japan and China. When queried, the vessel bearing the mark of People's Liberation Army Navy simply left.
For more details - East China Sea: Tokyo on guard after 'peculiar' Chinese naval ship sails near islets- Nikkei Asian Review
For more details - East China Sea: Tokyo on guard after 'peculiar' Chinese naval ship sails near islets- Nikkei Asian Review