Shinzo Abe: China new air defence zone move 'dangerous'
Japan's Prime Minister Shinzo Abe has described China's move to create a new "air defence identification zone" over disputed waters as "dangerous".
China's action had "no validity whatsoever on Japan", Mr Abe added.
China has voiced anger at Japanese and US objections to the new air zone, and lodged complaints with their embassies.
The zone covers disputed islands that are claimed and controlled by Japan. China says aircraft entering the zone must obey its rules.
Mr Abe told parliament on Monday that the zone "can invite an unexpected occurrence and it is a very dangerous thing as well".
"We demand China revoke any measures that could infringe upon the freedom of flight in international airspace,'' he added.
US Defence Secretary Chuck Hagel has called the move a "destabilising attempt to alter the status quo in the region".
"This unilateral action increases the risk of misunderstanding and miscalculations," Mr Hagel said in a statement.
"This announcement by the People's Republic of China will not in any way change how the United States conducts military operations in the region," he added.
Japan described China's move as an "escalation" on Saturday, after China announced the new zone.
On Sunday, Yang Yujun, a spokesman for China's Ministry of National Defence, said Japan's reaction was "absolutely groundless and unacceptable".
"We strongly require the Japanese side to stop all moves that undermine China's territorial sovereignty as well as irresponsible remarks that misguide international opinions and create regional tensions," Mr Yang said.
He also demanded that the US "earnestly respect China's national security [and] stop making irresponsible remarks for China's setup of the East China Sea Air Defence Identification Zone".
South Korea said it found it "regretful" that China's new zone partly overlapped with its own military air zone, and covered Ieodo, a submerged rock claimed by Seoul.
"I'd like to say once again that we have unchanging territorial control over Ieodo," Kim Min-seok, a South Korean defence ministry spokesman, said on Monday.
Taiwan also claims the Japan-controlled disputed islands known as Senkaku in Japan and Diaoyu in China. Taiwan said that it would "defend its sovereignty over the archipelago."
China said the air defence zone came into effect from 10:00 local time (02:00GMT) on Saturday.
Aircraft in the zone must report a flight plan, "maintain two-way radio communications" and "respond in a timely and accurate manner" to identification inquiries, China's Defence Ministry said.
Aircraft that did not follow such rules would be subject to "defensive emergency measures", the ministry added.
'Act of war'
The disputed islands in the East China Sea have been a source of tension between China and Japan for decades.
In 2012, the Japanese government bought three of the islands from their private Japanese owner, sparking mass protests in Chinese cities.
Since then, Chinese ships have repeatedly sailed in and out of what Japan says are its territorial waters.
In January, Japan said a Chinese frigate put a radar lock on a Japanese navy ship near the islands. China insists its ship was only using ordinary surveillance radar.
In September, Japan said it would shoot down unmanned aircraft in Japanese airspace after an unmanned Chinese drone flew close to the disputed islands.
China said that any attempt by Japan to shoot down Chinese aircraft would constitute "an act of war".
Since China's President Xi Jinping took power a year ago, Beijing has become more assertive in its territorial claims in the region, leading to rising tensions with many of its neighbours, the BBC's Martin Patience in Beijing reports.
The US has warned that a small incident or miscalculation in the East China Sea could escalate rapidly into a far wider and more serious crisis.
China is also engaged in territorial disputes with several South East Asian countries, including Vietnam and the Philippines. The disputes centre around ocean areas and two island chains in the South China Sea.