The US State Department is advising US air carriers to comply with China's demand that it be notified of any flights entering its new maritime air defence zone over the East China Sea, a move that comes a day after China sent fighter jets in to patrol the disputed air space.
Without prior notice, last week China declared that all aircraft entering the zone must notify Chinese authorities beforehand, and warned that it would take unspecified defensive measures against those that do not comply.
But the US, Japan and South Korea all sent military aircrafts into the airspace, defying the rules Beijing imposed on the area.
China's air force sent the warplanes on normal air patrols in the zone on Thursday, the Xinhua agency reported, citing air force spokesman Shen Jinke. He described the dispatch as "a defensive measure and in line with international common practices” in the Xinhua report.
He 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.”
A patrol also took place when the zone was declared on Saturday.
Some neighbouring countries and the US have said they will not honour the new zone and that it unnecessarily raises tensions.
South Korea's military said its planes flew through the zone this week without informing China and with no apparent interference.
Japan also said its planes have defied Beijing by 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 too would reject China's declaration.
State Department spokeswoman Jen Psaki said yesterday that the US remains deeply concerned about China's declared air identification zone.
But she says that it is advising US air carriers abroad to comply with notification requirements issued by China.