A Chinese naval drill near Japan has sparked concern from Tokyo, which in recent days lodged a protest with Beijing and made the rare decision to publicly disclose Chinese military movements.

In the last few weeks China’s two aircraft carriers, the Shandong and the Liaoning, have been conducting simultaneous drills in the Pacific, in an unprecedented move.

Chinese fighter jets have done hundreds of landings and take-offs from the carriers. A few came close to Japanese surveillance planes, prompting Tokyo to convey its “serious concerns” to Beijing.

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On Tuesday, the Japanese defence ministry released a map tracing the Chinese aircraft carriers’ daily positions since 25 May. Japan does not usually disclose details of foreign militaries’ movements.

It shows both carriers coming close to Japanese islands, and at times sailing through Japan’s exclusive economic zone.

The exclusive economic zone is an area beyond a country’s territorial waters where that country has exclusive rights to explore and exploit marine resources, but other countries are allowed freedom of navigation through it.

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