Japan's Chief Cabinet Secretary Hirokazu Matsuno said on Monday that Tokyo had lodged a protest with Russia over its military exercises around disputed islands near Japan's Hokkaido.
Matsuno also said that Russia informed Tokyo that it would conduct missile exercises around the disputed islands between April 18 and 22.
Separately, Russia last Friday said it would conduct missile launches and torpedo tests as part of a surprise inspection of its Pacific naval fleet.
(Reporting by Kaori Kaneko; Editing by Alex Richardson)