The President of Tokyo Electric Power Co. (TEPCO), owner of the crippled Fukushima No. 1 nuclear power plant in Japan, apologized for a nuclear emergency at the facility which is leaking radioactive substances, at a news conference Wednesday.

Masataka Shimizu said that TEPCO hoped to announce steps to restore the cooling system at the reactors at an early date. But he did not provide a specific timetable for the final end of the disaster.

The severity level of the accident at the nuclear power plant was raised by Japan's nuclear safety agency to 7, the worst on an international scale, from the current 5.

The ranking had only been applied to the 1986 Chernobyl accident. According to Japan's Nuclear and Industrial Safety Agency, the amount of radiation emissions released at the Fukushima plant was equivalent to 10 percent of that in the Chernobyl accident.

Since the March 11 quake and tsunami which crippled the plant, the company has been battling to restore the plant's critical cooling systems and prevent the plant from spewing more radioactive substances into the air, land and sea.

The power company is now facing a public relations crisis with the people and businesses affected by the nuclear crisis. Shimizu visited the Fukushima prefectural government office Monday to apologize in person for the nuclear disaster, but Fukushima Governor Yuhei Sato refused to meet the utility firm's chief.