US warships and planes that arrived in order to support Japan’s earthquake and tsunami relief efforts have been temporarily moved away due to low-level radiation from a nuclear power plant.

The US Seventh Fleet aircraft carrier USS Ronald Reagan and other US Navy ships in eastern Japan were repositioned as a precautionary measure.

17 military personnel aboard three helicopters were exposed to low levels of contamination, equal to one month’s natural background radiation from the sun, rocks or soil.

The carrier and its strike group were operating about 100 miles north-east of the damaged power plant but have moved to areas where they will not be in the path of radiation carried in the wind.

The Seventh Fleet spokesman in Japan commander Jeff A Davis stressed that the commitment to the relief mission would continue.