The Russians sent a "time bomb" PHOTO

The Defense Ministry said on Monday that four Russian ships were spotted in waters off the northern coast of Hokkaido, one of Japan's four main islands, as they passed through the La Perouse Strait.

The strait is one of five waterways where Japan has reduced its territorial waters and claims to maintain high seas corridors. All ships can exercise the right of transit passage in international navigation.

One of the vessels mentioned was the Yasen-class cruise missile submarine, which is considered the most advanced and quietest attack submarine in Russia.

Two Yasen-class submarines of nearly 14,000 tons have been assigned to the Russian Pacific Fleet, Krasnoyarsk and Novosibirsk.

After it was spotted, questions immediately began to arise as to why the Yasen-class submarine would leave its base near Petropavlovsk on the Kamchatka Peninsula, which is used by the nuclear-powered submarines of the Russian Pacific Fleet.

Especially since Japan is an ally of the US, while Russia has increased the level of military cooperation with North Korea.