Japan and South Korea followed the United States in sending military jets into China's new air defence zone, in an act of defiance that has raised tensions a notch over the East China Sea.
Beijing said it was fully aware of the flights, even as it lashed out at Japan and the US for opposing its new air rules.
A Chinese Defence Ministry spokesman said on Thursday that Tokyo has no right to point fingers at China, and the Japanese should revoke their own air defence zone first if they wanted China to do so.
In Tokyo, the policy panel of the ruling Liberal Democratic Party on Thursday approved a resolution demanding that China rescind the new zone, saying the unilateral move reflected "unreasonable expansionism", said wire agency reports.
Such are the stormy skies awaiting US Vice-President Joe Biden, who arrives in the region next week and is expected to quiz Chinese leaders on the aims behind the set-up of the Air Defence Identification Zone.
Scheduled to visit Tokyo, Beijing and Seoul, he is also expected to make a point to the Chinese about "an emerging pattern of behaviour" that has proven unsettling to its neighbours.
Beijing's establishment of the zone, which covers the East China Sea and includes airspace over the Diaoyu/Senkaku isles claimed by both China and Japan, has sparked uncertainty and protests from Canberra, Seoul, Tokyo and Washington.
On Tuesday, two US B-52 bombers flew into the zone. On Thursday, Seoul and Tokyo said they had also sent military jets into the area.
Seoul also requested that China change the outline of its zone during a meeting between Chinese and South Korean military officials in Seoul on Thursday, the Defence Ministry said. But Beijing declined to do so.
Tokyo said its coast guard and air force had continued to fly into the air space without notifying Beijing and had not encountered any resistance from China.
Beijing's new air zone has alarmed not just its East Asian neighbours, but also other countries which have competing
territorial claims, such as the Philippines.
The zone threatens the national security of affected countries and transforms the entire air zone into China's domestic airspace, Philippines' Foreign Affairs spokesman Raul Hernandez was quoted as saying by Agence France-Presse.
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