Nuclear sub blaze over but crew still on board
The Russian navy suffered its worst accident in August 2000, when the Kursk nuclear submarine exploded and sank during naval manoeuvres, killing all 118 crew members aboard.
A 2008 accident at the Nerpa nuclear-powered submarine killed 20 Russian seamen and injured 21 others when its fire-extinguishing system activated in error and spewed suffocating gas.
The Yekaterinburg is a Delta-IV-class nuclear-powered submarine that normally carries 16 nuclear-tipped intercontinental ballistic missiles. The 166-metre (548-ft) vessel hasa displacement of 18,200 tons when submerged.