KRONSHTADT, Russia (AP) — Hundreds of sailors have gathered at Russia's main naval cathedral to mourn the deaths of 14 seamen killed on one of the Russian navy's deep-sea submersibles.

The seamen and the priests who formerly served in the navy gathered on Thursday at the Kronshtadt Navy Cathedral on an island in the Gulf of Finland just off St. Petersburg. The men lit candles and took part in the prayer for the dead sailors.

A blaze on an unnamed deep-water submersible on Monday killed 14 people. The Russian Defense Ministry said there were survivors but didn't disclose details of the vessel, citing its secret mission.

Russian media reported it was the country's most secret submersible, a nuclear-powered vessel nicknamed the Losharik that has been designed for sensitive missions at great depths.