Video posted on YouTube and numerous social media sites appears to show a Kilo-class attack submarine in very close proximity to a raging fire with thick black smoke.
The footage was filmed in the Pacific port city of Vladivostok, home of the Russian Navy's Black Sea Fleet. Five submarines and a number of vessels are seen moored in close proximity to one another. Two submarines are very close to the blaze, with the fire possibly touching at least one submarine.
The Pacific Fleet's press service released a statement saying that the fire was part of "damage control exercises," which seems unlikely given the intensity of the blaze.
The Kilo-class submarine is one of Russia's main non-nuclear attack submarines. Designed and first fielded in 1980, the sub has been sold to and is used by a number of countries, including China, India, Iran, and Vietnam.
Kilo-class submarines based out of Russia's Black Sea Fleet were recently used to launch cruise missiles into Syria.
The Kilos have had a history of accidents, especially in India. In 2013 a fire erupted on the INS Sindhurakshak which caused an explosion that killed 18 crew members and sank the sub. In 2014, a fire started on the INS Sindhuratna that killed two Indian Navy officers. That fire was blamed on malfunctioning batteries.