Moscow - At least 12 people have died in an explosion at an ore mine in northern Russia, Interfax news agency reported Friday, citing the Russian Civil Defence.

The explosion took place in the Murmansk region as workers were setting 55 tons of high explosives in a mine shaft.

Four people were seriously injured in the blast, which caused a major fire in the mine.

The mine belongs to the company Apatit, which operates six locations.

The shaft where the blast occurred is eight kilometres from the mining town of Kirovsk. (dpa)