Bilateral naval exercises between the United States and Japan pose a security threat to Russia, Deputy Foreign Minister of the Russian Federation Igor Morgulov said.
The United States and Japan may provoke tensions in the region, the diplomat said.
"Such exercises are called defensive, but they are potentially offensive,” he said.
Moscow warned Tokyo about its attitude to the current exercises in diplomatic language.
"Russia will have to take measures in response in the interests of its defensive capability, should such practices expand. They should be prepared to this,” he concluded.
Naval exercises between Japanese Ground Self-Defense Force and the U. S. Marine Corps are to take place in Hokkaido in September-October.
The British press has recently reported that Russia was going to conduct a nuclear test either on the borders with Ukraine or in the Black Sea.