The Admiral Kuznetsov was undergoing an upgrade when the fire started amid welding work on Thursday morning.
Russia's only aircraft carrier, Admiral Kuznetsov, caught fire on Thursday morning during fix work in Russia's Arctic Sea port of Murmansk, according to Russian state news agencies.
According to the Zvezdochka shipyard, quoted by RIA Novosti, the ignition of power cables is responsible for the incident.
Crew members and civilian specialists were aboard the carrier at the time but have since been evacuated, dockyard representatives said.
The aircraft carrier was undergoing major repairs at Russia's Arctic port in Murmansk, also known as the Barents Sea port.
Authorities in Murmansk said 11 people were injured and 10 of them were hospitalized in intensive care units.
Firefighters were finding it hard to reach the blaze because of the heavy smoke caused by burning cables, Tass reported.
Russia's industry ministry told AFP that once the fire is out, officials would launch a probe and evaluate the extent of damage. The massive blaze follows a 70-ton crane crashing onto the Admiral Kuznetsov's deck in October 2018 when a mammoth floating dock holding the ship sank.
The Admiral Kuznetsov, which is not nuclear powered, became fully operational in 1995 and is the flagship of the Russian navy. When its rotation was over, the Admiral skulked back to Russian waters spewing black smoke and accompanied by an ocean-going tugboat - just in case the old carrier couldn't manage the trip under its own power.
On a 2016 mission in Syria, the carrier saw the loss of two onboard fighter jets in just three weeks.
The Kuznetsov also stopped off the coast of Libya in January 2017 and took aboard military strongman Khalifa Haftar, whom Russian Federation has reportedly backed in the country's long-running civil conflict.
The Admiral Kuznetsov was to be the first of a new fleet of Soviet aircraft carriers, but the Russian navy has been hit by a huge drop in funding since the 1991 collapse of the Soviet Union.