“This is a unilateral act that raises tensions … and it is unacceptable to us,” Kenji Kanasugi, the Foreign Ministry’s Asian and Oceanian Affairs Bureau director-general, told the Chinese Embassy in Japan, as quoted by the Kyodo News.
About 230 Chinese fishing boats reportedly approached the disputed islands accompanied by six China Coast Guard vessels late on Friday. Some of the Coast Guard vessels were allegedly equipped with guns.
The incident occurred just a day after Japan accused eight Chinese ships (both fishing and Coast Guard vessels) of briefly entering the territorial waters of Japan.
Japan has repeatedly accused the Chinese Navy of invading the Japanese territorial waters, in particular sailing in the contiguous zone near the disputed Senkaku Islands (Diaoyudao Islands) in the East China Sea, which are claimed by both Tokyo and Beijing.
In 2014, Japan and China agreed to reduce tensions over the disputed islands.