Russian authorities have confirmed reports of a spike in radioactivity in the air over the Ural Mountains. But the suspected source of the leak, a nuclear fuel processing plant, denied it was the source of contamination. <br/><br/>The Russian Meteorological Service said in a statement yesterday that it recorded the release of ruthenium-106 in the southern Urals in late September and classified it as extremely high contamination.<br/><br/>Russian authorities insisted, however, that the contamination posed no health risks. France's nuclear safety agency earlier this month said it 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.<br/><br/>Last month, when reports of a trace of ruthenium over Europe first appeared, Russia's state-controlled Rosatom corporation denied any leak. The corporation said it was working closely with international organisations to identify the potential source of the emission.