China dispatched several fighter jets to fly over its newly demarcated maritime air defence zone within days of US, Japan and South Korean military and civil planes flying through the zone in defiance of the new airspace rules established by Beijing.
Shi Jinke, spokesperson for the People's Liberation Army Air Force, said that the patrol mission on Thursday was carried out by several fighter jets and an early warning aircraft. He stressed that the mission was "a defensive measure and in line with international common practices."
Shi said China's air force is "on high alert and will take measures to deal with diverse air threats to firmly protect the security of the country's airspace."
On Friday, China continued its diplomatic defiance on the issue of setting up the Air Defence Identification Zone (ADIZ), saying it was within the country's sovereign right not only to do so but also patrol the zone.
China has been particularly scathing on Japan's reaction to the ADIZ.
"We would like to ask Japan to tell other countries whether Japan has an ADIZ or not. When Japan set up an ADIZ and expanded it several times, did Japan have consultations with other countries? How large is Japan's ADIZ? Japan is allowing itself to set fire but forbidding others to light even a lamp. Such acts of Japan and completely unreasonable and have ulterior motives," foreign ministry spokesperson, Qin Gang said at the regular press briefing when asked about tension flaring in the region because of China's new move.
China and Japan are locked in a bitter dispute over islands in the East China Sea and tension between the two countries has been intermittently flaring in the past several months.
"Regarding overlapping identification zone between China and Japan, China believes that we should improve communication to maintain joint security. With regard to differences over Diaoyu islands, China has always upheld that we should seek effective management of differences through dialogue and consultation. At present difficulty is Japan has been shying away from China's request. So Japan should not only say words but should also make tangible efforts," Qin said
On Thursday, Japan's military firmly insisted its own patrols over the area wouldn't stop because of Beijing's declaration.
"We have no intention to change this operation in consideration for China," Japanese chief cabinet secretary Yoshihide Suga was quoted by the Chinese state media as having said.
"We will continue the surveillance/patrol operation with strong determination to protect our territory against China's one-sided attempt to change the status quo by force."
Earlier this week, Washington sent two unarmed B-52 bombers through the airspace without first informing Beijing, just two days after China's announcement that it was establishing an ADIZ according to accepted international practice.
The Chinese air force flying its fighters over the zone is being seen as China's response to foreign flights - including the flight of two US warplanes - flying through without informing the Chinese authorities.
Beijing's initial lack of response was even criticised in the country's state-controlled media.
"Beijing needs to reform its information release mechanism to win the psychological battles waged by Washington and Tokyo," the Global Times, a nationalist tabloid published by the Communist Party's flagship People's Daily, said in an editorial.
South Korea's military said Thursday its planes flew through the zone this week without informing China and with no apparent interference. Japan also said its planes have been continuing to fly through it after the Chinese announcement, while the Philippines, locked in an increasingly bitter dispute with Beijing over South China Sea islands, said it also was rejecting China's declaration.