BEIJING - China's state media called Friday for "timely countermeasures without hesitation" if Japan violates the country's newly declared air zone, after Beijing sent fighter jets to patrol the area following defiant military overflights by Tokyo.
Japan and South Korea both said Thursday they had disregarded the air defence identification zone (ADIZ) that Beijing declared last weekend, showing a united front after US B-52 bombers also entered the area.
The zone includes disputed islands claimed by China, which knows them as the Diaoyus, but controlled by Japan, which calls them the Senkakus, and Beijing's ADIZ was condemned in Washington, Tokyo, South Korea and elsewhere.
China sent fighter jets and an early warning aircraft into the area
Thursday, the official Xinhua news agency reported after Tokyo said its military and coastguard had both flown through it.
Washington has security alliances with both Tokyo and Seoul, and analysts say that neither China nor Japan - the world's second- and third-biggest economies, and major trading partners of each other - want to engage in armed conflict.
But Beijing is facing mounting internal pressure to assert itself.
The Global Times newspaper, which often takes a nationalistic tone, said in an editorial Friday: "We should carry out timely countermeasures without hesitation against Japan when it challenges China's newly declared ADIZ.