JAPAN has reacted with alarm after China surged 40 fighters and bombers past its islands during a drill designed to test their ability to enforce a controversial ‘air defence zone’.

China’s People’s Liberation Army Air Force (PLAAF) sent nuclear-capable H-6K bombers, Su-30 heavy fighters, radar and tanker aircraft through the Miyako Strait in the East China Sea on Sunday.

Beijing says it was part of a “routine drill ... in accordance with the needs of the Air Force to defend national sovereignty and security, as well as to maintain peaceful development.”

China controversially declared an Air Defense Identification Zone (ADIZ) over much of the East China Sea in 2013. Japan and Taiwan also claim much of this airspace.

Video: Chinese Air Force sends over 40 aircraft to the Western Pacific for routine drill pic.twitter.com/nZJXXZC7uO — CCTVNEWS (@cctvnews) September 26, 2016

The Japanese Air Self-Defense Force (JASDF) scrambled fighters to observe the Chinese warplanes’ movements after it detected a group of eight approaching its territory.

While it was the first time Beijing has sent its warplanes through the strategically significant waterway, Japan’s minister of defence said they did not cross into national airspace.

Japan says it observed a mix of bombers and surveillance aircraft accompanied by one fighter jet as they passed between Okinawa and Miyakojima islands. This is close to the Senkaku/Diaoyou group of islands in the East China Sea islands over which both Japan and China claim ownership.

Beijing says this was just part of its 40-strong force sent into the area to test the PLAAF’s ability to conduct “reconnaissance and early warning, attacks on sea surface targets, and in-flight refuelling to test the Air Force’s fighting capacity on the high seas.”

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China recently sent a similar large force of long-range bombers and fighters through the Bashi Channel, the waterway between the Philippines and Taiwan, and deep into the Pacific Ocean.

Both narrow waterways represent strategically significant access points for China to the deeper Pacific.

With a string of heavily defended artificial islands nearing completion to enforce its claims to a ‘nine-dash line’ in the South and East China Sea, Beijing appears to be demonstrating its interest in what it considers its next line of strategic influence — the ‘second island chain’ which includes parts of Japan and the US island of Guam.

The demonstration of China’s growing reach with its modern bomber and fighter force also comes a week after Japan confirmed it would engage in joint military training exercises with the United States Navy in the South China Sea.

Beijing has reacted angrily to all suggestions Japan may play a role in that contested waterway.