MOSCOW: Four people were killed and several others injured in an explosion at a business in the city of Kopeysk in Russia's Chelyabinsk region, local authorities said.
Regional Governor Alexei Teksler said on Wednesday that there was no confirmation at this stage that a drone attack was involved, Xinhua news agency reported.
Earlier, Teksler added that all emergency services had arrived at the scene and a command centre had been established.