The head of the International Atomic Energy Agency said his body is ready to send a monitoring team upon request to check treated radioactive water set to be discharged from the crippled Fukushima No. 1 nuclear plant to address concerns over environmental impact.

"We can cooperate if the government of Japan so decides and invites us. We could cooperate in the whole spectrum of the operation, before, during and afterwards," IAEA Director-General Rafael Grossi said in a recent interview, citing the U.N. nuclear watchdog's expertise and experience.

"We are in preparatory talks" with the Japanese government over how to deal with the accumulating water, Grossi said.