The operator of the troubled Fukushima No. 1 nuclear power plant planned to release slightly radioactive air from the facility's No.2 reactor building, Kyodo News reported on Sunday.

Tokyo Electric Power Co., known as TEPCO, suspended the operation of a key system designed to clean up the highly radioactive water accumulated in the plant only hours after it started, due to sharp rise of radiation in a part of the system.

The Japanese government and the utility have been battling to keep the plant crippled by the devastating earthquake and tsunami in March under control. It is still leaking radioactive substances into environment.