Russia says it has filed a protest with Tokyo over planned joint drills between Japan's Air Self-Defense Force and the German and Spanish militaries.
The exercises are scheduled to take place next month in Hokkaido, which neighbors Russia's Far East.
Officials with Russia's foreign ministry said on Friday that the drills pose a threat to their country's national security and cannot be tolerated.
The ministry reportedly lodged a protest with the Japanese Embassy in Moscow.
Earlier this month, Japan's Defense Ministry announced a series of drills involving more than 30 French, German and Spanish aircraft between July 19 and 25.
The three European nations are members of NATO.
They will all join exercises near the Kanto region, but only Germany and Spain will train with the ASDF in Hokkaido.
The Russian ministry accused Japanese Prime Minister Kishida Fumio's administration of increasing tensions in Northeast Asia and the Asia-Pacific region, and warned of countermeasures.