BEIJING — China said it sent warplanes into its newly declared maritime air defense zone Thursday, days after the United States, South Korea, and Japan all sent flights through the airspace in defiance of rules Beijing says it has imposed in the East China Sea.
China's air force sent several fighter jets and an early warning aircraft on normal air patrols in the zone, the Xinhua agency reported, citing air force spokesman Shen Jinke.
The report did not specify exactly when the flights were sent or whether they had encountered foreign aircraft. The United States, Japan, and South Korea have said they have sent flights through the zone without encountering any Chinese response since Beijing announced the creation of the zone last week.
Shen described Thursday's flights as ''a defensive measure and in line with international common practices.'' He said China's air force would remain on high alert and will take measures to protect the country's airspace.
While China's surprise announcement last week to create the zone initially raised some tensions in the region, analysts say Beijing's motive is not to trigger an aerial confrontation but is a more long-term strategy to solidify claims to disputed territory by simply marking the area as its own.
China's lack of efforts to stop the foreign flights — including two US B-52s that flew through the zone Tuesday — has been an embarrassment for Beijing. Even some Chinese state media outlets suggested Thursday that Beijing may have mishandled the episodes.
''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.
Without prior notice, Beijing began demanding Saturday that passing aircraft identify themselves and accept Chinese instructions or face consequences in an East China Sea zone that overlaps a similar air defense identification zone overseen by Japan since 1969 and initially part of one set up by the US military.
But when tested just days later by the B-52 flights — with Washington saying it made no effort to comply with China's rules, and would not do so in the future — Beijing merely noted, belatedly, that it had seen the flights and taken no further action.
South Korea's military said Thursday that 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, while the Philippines, locked in a bitter dispute with Beijing over South China Sea islands, said it also was rejecting China's declaration.
Analysts question China's technical ability to enforce the zone due to a shortage of early warning radar aircraft and in-flight refueling capability. However, many believe that China has a long-term plan to win recognition for the zone with a gradual ratcheting-up of warnings and possibly also eventual enforcement action.
''With regard to activity within the zone, nothing will happen — for a while,'' said June Teufel Dreyer, a China expert at the University of Miami. ''Then the zone will become gradually enforced more strictly.''
That may wear down Japan and effectively change the status quo, she said.
The zone is seen primarily as China's latest bid to bolster its claim over a string of uninhabited Japanese-controlled islands in the East China Sea — known as Senkaku in Japan and Diaoyu in China. Beijing has been ratcheting up its sovereignty claims since Tokyo's privatization of the islands last year.