Japan has accused China of unilaterally exploring gas deposits in the East China Sea, in violation of an agreement to jointly develop disputed areas.
Japanese Chief Cabinet Secretary Osamu Fujimura told reporters on Wednesday that Japan protested to China after a flare was seen on Tuesday at a Chinese structure close to an undersea gas deposit. Japan has made similar complaints several times in the past.
“We have detected a flare, a sign that it is highly likely that there is a gas development going on,” Fujimura said. “Any unilateral exploration is unacceptable.”
The deposit, known as Kashi in Japan and Tianwaitian (天外天油氣田) in China, sits near the median line of the two countries’ overlapping exclusive economic zones.
Japan and China agreed in 2008 to suspend unilateral drilling in that field while continuing talks, but talks have stalled since 2010, following a diplomatic spat stemming from a maritime collision near disputed southern islands claimed by both countries, as well as Taiwan.
Fujimura said China’s activity around the disputed field violates the agreement.
A Japanese Ministry of Foreign Affairs official in charge of China affairs said on Wednesday that Beijing justified its activity by repeating China’e claim to sovereignty over the area.
Days earlier, Beijing criticized Tokyo for naming a group of uninhabited southern islands in nearby waters that both countries claim.
Four of the islands are in the disputed Senkaku, or Diaoyu (釣魚), chain in the East China Sea.
The islands, also claimed by Taiwan and China, have been a flashpoint in diplomatic relations.
Beijing said Tokyo’s naming of the islands was “illegal and invalid,” the ministry official said on condition of anonymity because of the sensitivity of the issue. Tokyo responded by saying the islands were an integral part of Japan.