Chinese naval aircraft, submarines and ships launched a new manoeuvre in the East China Sea, state media reported on Monday, firing rockets and torpedoes in the waters where China and Japan are locked in a dispute over a group of unoccupied islands.
The two neighbouring countries have overlapping claims over islands in the East China Sea known as Diaoyu to Beijing and Senkaku to Tokyo.
The tensions between the two countries were further inflamed on Tuesday with Japan's acceptance of a defence white paper portraying China's military activity in the East and South China Seas as a threat.
Last month, the Permanent Court of Arbitration in The Hague upheld a complaint brought by the Philippines about contested islets claimed by China in the South China Sea. The body of water contains key shipping routes and is believed to be rich in mineral and marine resources.
Analysts say the court's decision against China put Japan in a stronger position in its own territorial dispute.