In Moscow's first official reaction since it sailed three naval vessels near the disputed Senkaku Islands in the East China Sea, the Russian Foreign Ministry played down the move, calling it passage on the high seas.
In response to a query from Kyodo News, the ministry said Friday that it was a normal operation in keeping with international vessel navigation and that Russia was surprised by Japan's reaction.
The Defense Ministry said it spotted three Russian military ships in a contiguous zone near the Senkakus early Thursday.
The Russian Foreign Ministry did not comment on whether the Russian vessels' sailing was related to that of a Chinese naval ship seen in the contiguous zone at around the same time.
China and Taiwan both claim the Senkaku Islands, calling them Diaoyu and Tiaoyutai, respectively. China stepped up its claim after Japan purchased a major part of the islands from a Japanese individual and put them under state control in 2012.
While deepening relations with China, including in the military field, Russia has maintained a neutral position over the territorial row on the Senkakus between Japan and China.