(Reuters) - Russia's AS-31 deep-diving nuclear powered submarine, known by its nickname as Losharik, will go out for testing in June or July after completing years of repairs, the state TASS news agency reported on Wednesday, citing an unnamed military source.
"The repair of Losharik is almost complete," said the military source, who TASS said was close to the matter.
"After some remaining work, it is planned that it will go out for testing in June or July of this year."
That vessel, which was launched in 2003 and is one of the most secret submarines in the Russian fleet, has been in repairs since 2019 when a fire on board killed 14 sailors.
After the accident, Russia's defence ministry said the craft was nuclear-powered, but that the "nuclear elements" were fully isolated from the fire.
The source told TASS that after its repairs the vessel will retain the ability to dive to 6,000 meters (19,700 ft). TASS reported last year that the titanium hull of the submarine was not damaged, which ensures the vessel's diving capacity.
After launching its full-scale invasion of Ukraine in 2022, President Vladimir Putin has made beefing up the country's military capabilities a priority, saying Russia would continue to upgrade its nuclear forces and keep its combat readiness at a high level.
(Reporting by Lidia Kelly in Melbourne; Editing by Jamie Freed)