Radiation fears have prevented authorities from collecting as many as 1,000 bodies of victims of the March 11 earthquake and tsunami from within the 20-kilometer-radius evacuation zone around the stricken Fukushima nuclear plant, police sources said Thursday.

One of the sources said bodies had been ''exposed to high levels of radiation after death.'' The view was supported by the detection Sunday of elevated levels of radiation on a body found in Okuma, Fukushima Prefecture, about 5 km from the Fukushima Daiichi Nuclear Power Station.

The authorities are now considering how to collect the bodies, given fears that police officers, doctors and bereaved families may be exposed to radiation in retrieving the radiation-exposed bodies or at morgues, according to the sources.