After China called out Japan on its involvement in the South China Sea conflict as covered in this HNGN article, Japan has called out China's oil exploration activities close to the countries' borders in the East China Sea.

Japan's Defense Ministry has demanded that China immediately stop its construction of oil and gas platforms in the area, stating that the activities of China may end up tapping into oil reservoirs that extend into Japanese territory, reports The New York Times.

"We have confirmed that China has started construction of new ocean (exploration) platforms and we repeat our opposition to unilateral development by China and call for a halt," a report by the Japanese Defense Ministry said, according to The Open Digest.

Japan is also apprehensive about the possibility of China using the structures being built as radar stations or bases for drones or other aircraft. If China does use the platforms as an aircraft station, the country would gain a very strategic advantage over Japan in monitoring activities near the Senkaku, or Diaoyu, Islands.

Though the report did not disclose the actual locations of the Chinese operations, it did include satellite images of man-made islands that China has constructed in the South China Sea.

"China has rapidly moved ahead with land reclamation on seven reefs in the Spratly Islands and on some is building infrastructure including runways and harbors. Beginning with the U.S., this is a concern for the international community," the ministry report said.