Japan's Defense Agency dispatched four Maritime Self-Defense Force (MSDF) vessels Friday to try to rescue the trapped crew of a Russian military midget submarine that became unable to surface Thursday in the Pacific off the Kamchatka Peninsula.

The dispatch comes in response to a Russian request for Japanese assistance in rescuing the seven crew members as efforts by Russia's Pacific Fleet have failed, according to Japanese Foreign Ministry.

The first-ever dispatching of MSDF vessels abroad for rescue activities involving foreign vessels was made possible by the international emergency assistance dispatch law.

The oxygen supply necessary to keep all of the crew members alive will last only 24 hours, Kyodo News quoted a report of Russia's Interfax news agency. All seven crew members were reported alive as of Friday morning.

The MSDF vessels, including a submarine rescue vessel, are expected to take three to four days to reach the site of the incident, about 70 kilometers to the east of the Kamchatka Peninsula, according to the Defense Agency.

The crew members on the midget sub, which belongs to Russia's Pacific Fleet, were inspecting an underwater antenna about 200 meters below the surface when a wire to stabilize a cable for sending air to the antenna got tangled with the vessel's rudder, the agency said.

Source: Xinhua