A Russian navy submarine ruptured under air pressure Thursday as it underwent repairs at a dockyard in the port of Severodvinsk, Russia's news agencies reported Friday.
A tank in the main ballast of the vessel ruptured under air pressure, Oleg Frolov, chief engineer at the Zvyozdochka shipyard, where the incident happened, told Itar-Tass news agency by telephone.
"No one was injured, but around 25 square meters of the submarine's hull was damaged," a source in the Severodvinsk administration was quoted by Interfax news agency as saying.
Zvyozdochka General Director Nikolai Kalistratov said the incident was not an explosion, but a "popping."
"This is a performance situation, there was neither an explosion nor victims. Air under high pressure was fed to the submarine of the Russian Navy, which is undergoing maintenance repairs. The decision to feed air to the submarine was wrong, it resulted in a popping," Kalistratov was quoted by Interfax as saying.
The general director refused to specify whether the submarine is of a nuclear class or not.