A diplomatic tit-for-tat between Japan and China has escalated as Tokyo lodged a new protest with Beijing over the drilling of gas fields in disputed waters in the East China Sea.
The protest, lodged Tuesday, is centered on Japan's discontent over China's alleged breach of bilateral efforts toward joint development, Chief Cabinet Secretary Osamu Fujimura told a news conference Wednesday.
He underlined Japan's concern over "signs of unilateral development" by China that have been observed in the areas recently.