More than 20 people were killed Saturday during the sea trial of a Russian nuclear submarine, officials said.

The 21 people injured when the fire extinguishing system went off accidentally were transferred to the Admiral Tributs, a large anti-submarine vessel, the Novosti news agency reported.

Capt. Igor Dygalo said the dead included shipyard workers and members of the submarine's crew. The name and class of the submarine were not released, but Dygalo said it was part of the Pacific fleet.

The nuclear reactor was not damaged.

There were 208 people on board the vessel at the time, 81 of them members of the military.

The submarine was headed to a temporary base, escorted by the Admiral Tributs and a rescue vessel, Sayany.

First Deputy Defense Minister Alexander Kolmakov and Admiral Vladimir Vysotsky, the commander-in-chief of the navy, were en route to the area, Dygalo said.