President Obama said Thursday he has asked nuclear regulators to do a comprehensive review of the safety of U.S. plants in light of the disaster in Japan, saying "nuclear energy is an important part of our own energy future."

Obama said he made the request to the Nuclear Regulatory Commission. He spoke after the commission's head said that it could take weeks to bring the crippled nuclear complex in northeastern Japan under control.

In brief remarks at the White House, following a trip to the Japanese Embassy to express his condolences, Obama also sought to assure the nation that the disaster currently posed no threat to the United States.

"We do not expect harmful levels of radiation to reach the West Coast, Hawaii, Alaska or the U.S. territories in the Pacific," Obama said, repeating the remark for emphasis.