A small fire occurred Sunday at the Tomari nuclear power plant in western Hokkaido, operator Hokkaido Electric Power Co. said, adding that there was no radiation leak.

According to the utility, smoke rose from one of the buildings in the compound in an area that is separate from the plant's three reactor buildings, at around 2:45 p.m. Sunday.

A local fire department is investigating the cause. At the time of the fire, workers were welding metals at the building and there were heat-insulating materials nearby, the utility said.