Russia is refuting allegations that it is the source of a mysterious radiation cloud moving across Scandinavia.Energy authorities in Sweden, Finland, and Norway observed a safe, but remarkable, increase of three radioactive isotopes in June.

The radiation comes "from the direction of Western Russia," the the Netherlands' National Institute for Public Health and the Environment said.A spokesperson for Russia's nuclear energy body said the Kola and Leningrad plants, near the border with Finland, are working as normal.

Russia has a long and turbulent history with nuclear power, including regular attempts to cover up leaks and explosions.Russia on Saturday denied allegations that it was behind a cloud of radiation seeping into southern Scandinavia.

Energy watchdogs in Finland, Sweden, and Norway reported increased levels of the Ru-103, Cs-134, and Cs-137 radioisotopes in June, according to The Associated Press (AP).The countries did not accuse Russia directly, but the Netherlands' National Institute for Public Health and the Environment (NIPHE) said on Friday that an analysis of the data showed that the radiation comes "from the direction of Western Russia."

Last week, energy watchdogs in Finland, Sweden, and Norway reported increased levels of the Ru-103, Cs-134, and Cs-137 radioisotopes in June, according to The Associated Press (AP).The countries did not accuse Russia directly, but the Netherlands' National Institute for Public Health and the Environment (NIPHE) said on Friday that an analysis of the data showed that the radiation comes "from the direction of Western Russia."

The pattern "indicates damage to a fuel element in a nuclear power plant," the NIPHE said.

In response, a spokesperson for Rosenergoatom Concern, a branch of the centralized Russian nuclear energy company Rosatom, denied that there had been a leak.Two nuclear powerplants in western Russia, the Leningrad and the Kola, are "working in normal regime," the spokespersontold state news agency TASS on Saturday.

"There have been no complaints about the equipment's work," the representative said. "Radiation levels at both NPPs and surrounding areas remained unchanged in June."The Swedish Radiation Safety Authority said last Tuesday it couldn't pinpoint the exact source of the increased levels.The International Atomic Energy Agency said it is aware of the reports, and has contacted Russia for clarification.

Russia has a long and turbulent history with nuclear power, including regular attempts to cover up leaks and explosions.