Japan said Friday that it would strengthen intelligence-gathering and monitoring after the Russian Defense Ministry announced a day earlier that two navy submarines had test-fired Kalibr cruise missiles in the Sea of Japan, the latest in a series of high-profile military exercises in the region since Moscow’s invasion of Ukraine.

“In recent years, Russian military activities, including the deployment of state-of-the-art equipment and training exercises, have tended to increase in the vicinity of Japan,” Defense Minister Nobuo Kishi told a news conference. “We will continue to collect information and conduct vigilant monitoring with a sense of concern.”

On Thursday, the Russian Defense Ministry announced that submarines belonging to the country’s Pacific Fleet had launched the advanced cruise missiles, the same weapons being used in Ukraine, from submerged positions in the Sea of Japan, successfully hitting a mock target designed to resemble an enemy vessel. The ministry did not reveal the date or actual location of the launches.