At least five workers were killed in a blast at an explosives plant in Russia’s Ryazan region southeast of Moscow, emergency officials said Friday.

According to the state-run news agency RIA Novosti, a gunpowder workshop at the Elastic synthetic fiber plant caught fire and triggered explosions.

The Ryazan region’s crisis response group initially said three people were killed, then updated the death toll to four.

Russia’s Emergency Situations Ministry placed the death toll at five.

Both agencies said the total number of wounded was still being determined.