MOSCOW, May 6 (Xinhua) -- Three people were killed after an explosion struck an ammonia plant of fertilizer producer Uralchem in Russia's Perm region, local media reported Monday.

The incident occurred during maintenance work, a representative of the local emergency services was quoted by the RIA Novosti news agency as saying.

There is no threat to the staff or local residents and the plant is currently operating normally, the official said.

Uralchem Holding P.L.C., a company incorporated in Cyprus, is one of the largest producers of nitrogen and phosphate fertilizers in Russia and other countries of the Commonwealth of Independent States.