BEIJING - Asian aviation officials have said that airlines would have to inform China of their flight plans before entering airspace over waters disputed with Japan, forcing carriers to acknowledge China's authority over a newly declared "Air Defence Identification Zone".
China published coordinates for the zone on the weekend. The area, about two-thirds the size of the United Kingdom, covers most of the East China Sea and the skies over a group of uninhabited islands at the centre of a bitter row between Beijing and Tokyo.
While China said that the new rules would not affect "normal operations" for international flights, it added that it would take "defensive emergency measures" against aircraft that failed to identify themselves properly.
Japan and the United States have sharply criticised the move, warning of an escalation into the "unexpected" if Beijing enforces the rules.
China's Defence Ministry said yesterday that it had lodged protests with both countries' embassies in Beijing, saying that such remarks were unfounded and irresponsible.
A transport ministry official in Seoul said that South Korean planes flying in the new zone would notify China's civil aviation authorities of their flight plans.
Yi Shin-Juang, deputy director of the air traffic service division of the Taiwan Civil Aeronautics Administration, said that Taiwanese carriers would issue similar notifications, but would not be required to adjust flight paths.
An official at the Japan Civil Aviation Bureau said that Japanese airlines flying through the region to non-mainland Chinese destinations would likely need to inform China of their plans.
"Airlines have been advised to take greater care in the area," said another bureau official.
Korean Air said that China's proclamation meant that flight plans would have to be delivered to Chinese authorities but the routes that its pilots took would not be affected.
Japan Airlines and ANA said that the zone had not affected their flights through the area. The zone was a problem for Japan, the US and other countries that may be wary of any acknowledgement of China's claims over the area, Asian and Western diplomats said.
"No one wants to be in a position whereby following Chinese instructions you are giving tacit acknowledgement of their sovereignty over a disputed area," one Asian diplomat said.
"And there is a fear that is precisely the game that is being played - it seems no accident that the disputed Senkaku islands are now in the heart of overlapping zones," the diplomat added, referring to the disputed islands which are known as Diaoyu in China.
China's official Xinhua news agency said that the rules came into force on Saturday and that the Chinese air force conducted its first patrol over the zone. The patrol included early warning aircraft and fighters, it said.
Japanese Prime Minister Shinzo Abe said that China was forcing other countries to conform to its rules. "It's a unilateral step, changing the status quo in the East China Sea," Mr Abe said in parliament yesterday, keeping up the chorus of criticism from Tokyo.
"It escalates the situation and could lead to an unexpected occurrence of accidents in the airspace. It is an extremely dangerous measure and our government has strongly expressed its concerns about it," he added.
US Secretary of State John Kerry over the weekend urged China to exercise restraint, saying that freedom of overflight was essential to stability and security in the Pacific.
China's Defence Ministry said that it was within the country's right to set up the zone. "Japan's remarks are unjustified - China will never accept them," spokesman Yang Yujun said.
"We reiterate that the purpose of China's approach is to defend national sovereignty and territorial airspace security, maintain the order of airspace flight, and is an effective exercise of our right of self defence," Mr Yang said.
He said China's move complied with the UN charter and international law. The United States should stop taking sides in the dispute, and stop making "irresponsible remarks" on the new zone, Mr Yang added.
"The United States, on the issue of the Diaoyu islands, must earnestly not take sides, not make inappropriate remarks and not give the wrong signal to Japan and encourage (its) risky behaviour," he said.
While Washington does not take a position on the sovereignty of the islands, it recognises that Japan has administrative control over them and is therefore bound by treaty to defend Japan in the event of an armed conflict.
Tensions flared last year between Beijing and Tokyo when the Japanese government bought three of the islands from a private landowner to fend off a potentially more inflammatory purchase by the Tokyo metropolitan government, at the time headed by nationalist governor Shintaro Ishihara.