Tokyo Electric, also known as Tepco, is working to contain radioactive water at the Fukushima plant, which suffered meltdowns and hydrogen explosions after it was hit by a massive earthquake and tsunami in March 2011.

Tepco President Naomi Hirose told lawmakers during a parliamentary hearing on Friday that contaminated water at the plant was "under control", as Prime Minister Shinzo Abe had assured the International Olympic Commission in Buenos Aires earlier this month.

(Reporting by Mari Saito and Kentaro Hamada; Editing by Edmund Klamann)