Four Russian warships were spotted sailing through a strait in northeastern Japan Wednesday, possibly transporting troops and combat vehicles to Ukraine, the Japanese Defense Ministry said.

Four Russian tank landing ships were confirmed to have passed through the Tsugaru Strait between Japan's main island of Honshu and its northernmost main island of Hokkaido from the Pacific Ocean into the Sea of Japan.

Supplied photo taken on March 16, 2022, shows a Russian navy tank landing ship with vehicles on its deck. (Photo courtesy of Japan Joint Staff)(Kyodo)

Japanese Maritime Self-Defense Force first spotted two Russian tank landing ships about 70 kilometers east-northeast of Shiriyazaki, Aomori Prefecture, at around 8 p.m. Tuesday, and two others about 220 km east-northeast of Shiriyazaki, at around 7 a.m. Wednesday.

The four vessels then entered the Tsugaru Strait, about 700 km east of Russia's far eastern city of Vladivostok.