A fire on a Russian warship in the Pacific killed two sailors, the navy said on Thursday, the latest in a series of accidents that have raised doubts about the safety of Russia's fleet.

Russia's navy is under renewed scrutiny because the Kremlin is using it to project its newly assertive foreign policies, including by sending a nuclear-powered cruiser to the Caribbean later this year.

The Marshal Shaposhnikov anti-submarine destroyer limped into Vladivostok's harbour, home of Russia's Pacific fleet, on Thursday after the fire.

"One sailor serving under contract, and one conscripted sailor, who were in the section where the accident happened, died," the navy said in a statement. "The preliminary reason for the fire is a technical failure."

A series of accidents has dented the reputation of Russia's navy, which suffered years of neglect and under-funding after the collapse of the Soviet Union.

The most high profile incident was the 2000 sinking of the Kursk nuclear submarine when all 117 crew died.

The United States has questioned the navy's reliability, with a State Department spokesman quipping that the nuclear-powered cruiser 'Peter the Great' may break down before it reaches the Caribbean for joint exercises with Venezuela in November.

The exercises are the Russian navy's first major manoeuvres on the United States' doorstep since the Cold War.

In July, Russia's navy announced plans for a major expansion, including the building of new aircraft carriers. The navy has only one aircraft carrier in service.

Navy officials said they suspected the fire on the Marshal Shaposhnikov had broken out in the engine room when an oil pipe ruptured during a naval exercise in the Sea of Japan.

Built in the 1980s, the Marshal Shaposhnikov carries anti-submarine munitions and helicopters.