BEIJING (AFP, AP) - China scrambled fighter jets to monitor US and Japanese aircraft which entered its newly declared air zone on Friday, state media reported.

"Several combat aircraft were scrambled to verify the identities" of US and Japanese aircraft entering the air defence identification zone that Beijing declared last weekend, the state-run Xinhua news agency said, citing air force spokesman Shen Jinke.

The Chinese aircraft, which included at least two fighter jets, identified two US surveillance aircraft and 10 Japanese aircraft including an F-15 warplane, Colonel Shen said.

Col Shen said that the air force had a mission to monitor foreign aircraft inside the zone "throughout the entire process, with timely identification".

The state-run China News also quoted Col Shen as saying that two Chinese fighter jets identified and monitored the two US and 10 Japanese aircraft during their flights through the zone early on Friday, but made no mention of any further action.

China announced last week that all aircraft entering the zone - a maritime area between China, Taiwan, South Korea and Japan - must notify Chinese authorities beforehand.

Neighbouring countries and the US have said they will not honour the new zone and have criticised the move, saying it unnecessarily raises tensions.

China's announcement of the zone, which covers islands which are the subject of a bitter territorial dispute with Japan, has been seen as raising tensions in the region.

China's state media called Friday for "timely countermeasures without hesitation" if Japan violates the country's newly declared air zone.

Japan and South Korea both said on Thursday they had disregarded China's new air defence identification zone (ADIZ), showing a united front after US B-52 bombers also entered the area.