Russian authorities have confirmed reports of a spike in radioactivity in the air over the Ural Mountains.
France's nuclear safety agency earlier this month recorded radioactivity in the area between the Volga River and the Ural Mountains from a suspected accident involving nuclear fuel or the production of radioactive material.
It said the release of the isotope Ruthenium-106 posed no health or environmental risks to European countries.
The Russian Meteorological Service said in a statement today that it recorded the release of Ruthenium-106 in the southern Urals in late September and classified it as "extremely high contamination".
After the first reports, Russia's state-controlled Rosatom corporation said in a statement last month that it had not come from its facilities.