Updated

Japan's industry minister has visited the crippled Fukushima Dai-Ichi nuclear plant and promised urgent government action to curb leaks of radiation-contaminated water.

Trade Minister Toshimitsu Motegi said Monday that lax maintenance by the plant's operator was largely to blame for leaks of water from storage tanks surrounding the plant, which suffered triple meltdowns after the massive earthquake and tsunami in 2011.

He said the government would be taking charge and stepping up patrols of the tanks to prevent overflows. A leak last week was the fifth and worst from a tank at the plant.

Tokyo Electric Power Co., operator of the nuclear plant, saw its stock price plunge nearly 6.9 percent on Monday as investors dumped shares following the release over the weekend of further details on the crisis.