(Reuters) – Japan’s two biggest airlines have bowed to a government request to stop filing flight plans demanded by China on routes through a new Chinese air defense zone, whose creation has ratcheted up tensions over the bitterly disputed region.

Both ANA Holdings and Japan Airlines, which had been informing China’s aviation authorities of flights through the zone established in the East China Sea on Saturday, will stop doing so from Wednesday, spokesmen for the carriers said.

Japan and the United States sharply criticized the creation of the defense area, seen as a bid to chip away at Tokyo’s claim to administrative control over the maritime region.

The region includes small uninhabited islands known as the Senkaku in Japan and the Diaoyu in China, which are at the center of a row between Beijing and Tokyo.

By demanding carriers file flight plans through the zone or risk being intercepted by military jets, China is forcing carriers including JAL and ANA to effectively acknowledge Beijing’s authority over the “Air Defense Identification Zone”, which is about two-thirds the size of the UK.

But by persuading ANA, JAL and other carriers to ignore the zone, Japan’s Primes Minister Shinzo Abe may be calling China’s bluff.

Abe’s government earlier warned of possible unexpected consequences if Beijing enforced the rules. U.S. Defense Secretary Chuck Hagel described the move a “destabilizing attempt to alter the status quo in the region”.

China’s Defense Ministry countered by lodging protests with the U.S. and Japanese embassies in Beijing.

Civil aviation officials from Hong Kong and Taiwan on Monday said their carriers entering the zone must send flight plans to Chinese aviation authorities. A transport ministry official in Seoul said South Korean planes would do the same.

SOURCE REUTERS