China will conduct naval exercises on Friday to practise defending territorial sovereignty in the East China Sea, state media said, amid strained ties between Tokyo and Beijing over a disputed island chain.

Both sides have adamantly pressed their claims to the Tokyo-controlled islands -- known as the Diaoyus in China and Senkakus in Japan -- and the row has caused diplomatic and economic fallout between the historic rivals.

"The exercise is aimed at... sharpening their response to emergencies in missions to safeguard territorial sovereignty and maritime interests," the official Xinhua news agency on Thursday quoted a navy statement as saying.

China has sent maritime surveillance ships and fisheries patrol vessels near the islands in recent weeks as the row has escalated, and on Wednesday a Chinese naval flotilla passed near separate islands that are internationally recognised as Japanese.

As well as naval vessels, Friday's exercise will include vessels from the marine surveillance agency and fishery administration, both of which the statement said "have been stalked, harassed and even intentionally interfered with by foreign vessels".

The three bodies have staged joint exercises before, it said.

The dispute flared in August after nationalists from both countries landed on the islands and Tokyo later nationalised some of them.

Chinese citizens staged massive demonstrations in many cities, forcing Japanese firms to suspend or reduce operations, and official events, passenger flights and other events involving the two sides have been cancelled.

Trade between the two countries topped $300 billion last year.

Reports this week said Japan and the United States were considering holding a joint military drill to simulate retaking a remote island from foreign forces.

The exercise, part of broader joint manoeuvres to start in early November, would use an uninhabited island in Okinawa, Jiji Press and Kyodo News agencies quoted unidentified sources as saying.