Most of the injuries were sustained when the force of the explosion shattered windows and damaged walls of nearby houses, officials said, adding that seven people were hospitalised, including one in serious condition.

The military was unable to determine the cause of the fire in the arsenal, which stocked naval and artillery shells.

It was the fifth such incident in the Pacific Fleet's arsenals.

In the most recent incident last autumn, fire devastated a weapons stockpile in the city of Vladivostok, raging for a full day before being brought under control.

WAR.WIRE