The container, about 20 centimetres square, was found along the highway between Yekaterinburg and Tyumen on Tuesday, ministry spokesman Viktor Beltsov said, according to AP. The container was emitting radiation at a level of 2,800 microroentgens, he said. Natural background radiation in that region of Russia is about 50 microroentgens. There were no immediate details on what substance it may have contained or on its origin, the news agency reported.