Hong Kong (CNN) -- Tensions are running high in the skies between China and Japan -- and the United States is refusing to stay on the sidelines. After Beijing upset the region by declaring a new air defense zone over a large part of the East China Sea, two unarmed U.S. B-52 bombers flew through the area in what the U.S. State Department said was a planned military exercise. The U.S. aircraft ignored China's new demands that planes that fly through the zone identify themselves and submit flight plans to Chinese authorities -- despite Beijing's warnings that it could take military measures against aircraft that failed to comply.
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The Chinese military says it identified the U.S. military aircraft
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U.S. official: B-52s didn't tell Beijing about flights over China's new air defense zone
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Washington and Tokyo have criticized Beijing's declaration of the new zone
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They say it increases tensions and raises risks of an incident
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After news of the @placeholder flights emerged, the Chinese defense ministry responded cautiously Wednesday, saying it had monitored the planes' activity on the edge of the air defense zone.
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At a regular briefing later Wednesday, a journalist asked a @placeholder foreign ministry spokesman if Beijing is concerned it will now be seen as a "paper tiger."
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From a legal point of view, he said, the airlines probably don't have to report their plans and follow all the rules requested by @placeholder.