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.
Obama said that the United States "has a responsibility to learn from these events."
The president also defended the recommendation of federal nuclear safety officials of a 50-mile evacuation zone around the crippled nuclear power plan for American troops and citizens in Japan, even though it's far larger than the zone spelled out by Japanese officials.
"This decision was based on a careful scientific evaluation," Obama said. "Beyond this 50-mile radius, the risks do not currently call for an evacuation."
Japanese officials have established a 12-mile evacuation zone and have said that people living between 12 and 20 miles from the plant should stay inside.
"We have seen an earthquake and tsunami render an unimaginable toll of death and destruction on one of our closest friends and allies in the world," said Obama. "And we've seen this powerful natural disaster cause even more catastrophe through its impact on nuclear reactors that bring peaceful energy to the people of Japan."
For emergency information, assistance, and locating family in connection with earthquake in Japan: http://www.facebook.com/l/6b2e3a9CLMNbUwBsOw1jOL8d5aw/www.jhelp.com
Phone numbers in US and Japan:
202 559 4683
800 373 1110
0570 000 911
011 81 90 7170 4769
011 81 90 3080 6711