Ukrainian officials say a roof section at the exploded Chernobyl nuclear power plant has collapsed causing no injuries and leaving radiation levels unaffected.

Maya Rudenko, spokeswoman for the Chernobyl nuclear power plant, said a 600-square-meter section of the roof over the turbine hall at energy block No. 4 collapsed Tuesday. 

Rudenko emphasized, however, that the affected area is about 50 meters away from the exploded reactor. She said Wednesday that radiation levels were normal and there was no danger to the public, so ``everybody should be absolutely calm.''

The Emergency Situations Ministry said that the roof collapse was caused by heavy snowfall.

The April 1986 explosion at Chernobyl has forced the evacuation of 115,000 people and a 30-kilometer area around the plant remains largely off-limits. (AP)