MOSCOW (AP) — An explosion and fire at a gunpowder factory in Russia on Friday killed at least seven people, while nine remain missing, emergency officials said.

The Emergency Situations Ministry said the explosion hit the Elastik factory in the Ryazan region, about 270 kilometers (about 167 miles) southeast of Moscow.

Russian news reports said that all those missing are believed dead. One person was hospitalized with serious injuries, according to local officials.

The ministry said 170 emergency workers and 50 vehicles were involved in dealing with the fire.

Officials are looking at violations of safety procedures or a short circuit among possible causes.