At least six people were killed and two others were injured in a blast at an explosives factory in the Samara region of central Russia, state news agencies reported Friday. "Eight people were injured, six of whom died" at the Promsintez plant in the city of Chapayevsk, the RIA Novosti news agency cited the emergency services as saying. The cause of the blast was not immediately clear.The Promsintez plant is a manufacturer of industrial explosives and chemicals that specializes in ammonal, nitric acid, technical sulfuric acid, explosive cartridge detonators and other products.Friday’s deadly blast is just one of several to have recently taken place at Russian explosives factories.Last month, five people were killed in a blast at an explosives factory in Russia’s central Tambov region.

At that time, Tambov Governor Maxim Yegorov said the explosion was caused by “human error” and “definitely not [the result of] a terrorist attack.” In May, two workers were killed at an explosives plant in the Perm region, located 1,000 kilometers east of Moscow.In Kazan, one worker was injured in a similar incident that occurred in April at a local plant.AFP contributed reporting.