Nuclear Leak Forces Russian Icebreaker Back to Port

Russia launched an urgent rescue mission Thursday after one of its atom-powered icebreakers developed a nuclear leak in the frozen seas of the Arctic and was forced to abandon its mission, Agence France Presse reported.

The Rosatomflot nuclear fleet said in a statement that "insignificant increase in activity" had been reported on board its Taimyr icebreaker.

But the incident was serious enough to force the mammoth vessel to abandon its mission and try to track its way back to port in the northwestern city of Murmansk.

"What we are most concerned about right now is movement along the waterways," the RIA Novosti news agency quoted top Rosatomflot official Andrei Smirnov as saying.

The fleet official said another icebreaker was being dispatched to the region to help the vessel's journey back to port.

The incident was reported in the Kara Sea -- a part of the Arctic Ocean that rests about 2,000 kilometers (1,300 miles) east of Norway's border.

Officials said the increased levels of radiation were initially reported in the air ventilation system surrounding the nuclear reactor core.

They added that radiation levels remained normal outside the outer protecting covering.

But other details -- including how many people were on board the ship -- remained unclear and one part of the Russian statement suggested that officials were looking into the possibility of the situation becoming more serious.

"If the situation deteriorates, the reactor system will be shut down and the cooling process will begin," Rosatomflot said.

Rosatomflot stressed that the seriousness of the event at the moment could be registered as a zero on the seven-point International Nuclear and Radiological Event Scale -- a level officially defined as "bearing no safety significance".