Vessel 'holed by drifting ice', says regional Emergency Ministry source.
Fate of 13 still unknown as rescue efforts continue.
Four bodies found, search underway for the other six on board a capsized patrol boat in poor weather.
Possible 'explosion' at time of Tyva Republic helicopter crash, say experts, as mourning period expected for up to 14 people killed.
Incredible escape for dozens more as carriages overturn and fall into sea amid hurricane-force winds.
Helicopter crash kills three including leader of expedition to find schooner lost in infamous 1914 tragedy.
Siberian Natalia Fileva, 55, co-owner of S7 airline, perished alongside her father in private plane tragedy in Germany.
From the Urals to Pacific people this week joined the rest of Russia in marking the massacre in which 334 were killed.
Russian ecologist says his undercover trip shows Arctic ecosystem is irreversibly damaged, as whistleblower in ecological watchdog quits and leaves town.
Lyubov Morekhodova glides over the pure ice on skates made by her father not long after World War Two.