Two U.S. military aircraft have flown around disputed islands in the East China Sea without informing China, the Pentagon said on Tuesday, defying China's declaration that the region falls into a new airspace defense zone.
"We have conducted operations in the area of the Senkakus. We have continued to follow our normal procedures, which include not filing flight plans, not radioing ahead and not registering our frequencies," spokesman Colonel Steve Warren said, using the Japanese name for the islands.
There was no Chinese response, Warren said.
China published coordinates for an "East China Sea Air Defence Identification Zone" over the weekend and warned it would take "defensive emergency measures" against aircraft that failed to identify themselves properly in the airspace.
The zone covers most of that sea and includes the skies over islands at the heart of a territorial dispute with Japan.
The United States and close ally Japan have sharply criticized the move, with U.S. Defense Secretary Chuck Hagel calling it a "destabilizing attempt to alter the status quo in the region." He said on Saturday the United States would not change how it operates in the region.
The White House said that the dispute between China and Japan over the islands should be solved diplomatically.
"The policy announced by the Chinese over the weekend is unnecessarily inflammatory," White House spokesman Josh Earnest told reporters in California, where President Barack Obama is traveling.
"These are the kinds of differences that should not be addressed with threats or inflammatory language, but rather can and should be resolved diplomatically," he said.
Experts said the Chinese move was aimed at chipping away at Tokyo's claim to administrative control over the area, including the tiny uninhabited islands known as the Senkaku in Japan and the Diaoyu in China.
While Washington does not take a position on the sovereignty of the islands, it recognizes that Japan has administrative control over them and is therefore bound by treaty to defend Japan in the event of an armed conflict.
The Pentagon said the flights took place on Monday evening Eastern Standard Time and "involved two aircraft flying from Guam and returning to Guam" on a training mission.
Warren said the U.S. military aircraft were neither observed nor were contacted by the Chinese aircraft.
China's Defence Ministry said on Monday it had lodged protests with the U.S. and Japanese embassies in Beijing over the criticism from Washington and Tokyo of the zone.
China also summoned Japan's ambassador, warning Tokyo to "stop (their) words and actions which create friction and harm regional stability", China's Foreign Ministry said. Meanwhile, Tokyo and Seoul summoned Chinese diplomats to protest.
In addition, China sent its sole aircraft carrier on a training mission into the South China Sea on Tuesday amid maritime disputes with the Philippines and other neighbors and tension over its airspace defense zone in waters disputed with Japan.
The Liaoning, bought used from Ukraine and refurbished in China, has conducted more than 100 exercises and experiments since it was commissioned last year but this is the first time it has been sent to the South China Sea.
The Liaoning left port from the northern city of Qingdao accompanied by two destroyers and two frigates, the Chinese navy said on an official news website.
© 2015 Thomson/Reuters. All rights reserved.