President Obama tried today to calm fears that nuclear radiation from the ongoing disaster in Japan might reach American shores.

"I want to be very clear: We do not expect harmful levels of radiation to reach the West Coast, Hawaii, Alaska, or U.S. territories in the Pacific," Obama said in a statement delivered at the White House this afternoon.

In his statement -- the president didn't take questions from reporters -- Obama offered an update on the crisis in Japan where authorities are battling to prevent a full reactor meltdown at the Fukushima Daiichi nuclear plant. The president also used the opportunity to reiterate his commitment to making safe nuclear power a part of the United States energy program.

Obama said "exhaustive studies" have established that American nuclear facilities are safe from a variety of potential disasters. But he said that in light of what happened in Japan he's asked the Nuclear Regulatory Commission to conduct a "comprehensive review" of American power plants.

But as some on Capitol Hill and in the energy industry have raised questions about the future of nuclear power in light of the disaster, Obama came to defense of the industry.

"Here at home, nuclear power is also an important part of our own energy future," Obama said.

Throughout his remarks Obama offered praise for the "courageous responders" and the American military and civilian personnel who have deployed to help.

"To date, we've flown hundreds of missions to support the recovery efforts, and distributed thousands of pounds of food and water to the Japanese people," he said. "We've also deployed some of our leading experts to help contain the damage at Japan's nuclear reactors."

Obama also had a message for the Japanese people: You are not alone.

The appearance this afternoon came just after the president returned from an unannounced visit to the Japanese Embassy in Washington, D.C., in which he signed a condolence book for those affected by the powerful earthquake and tsunami that struck Northeast Japan last Friday.

"The memory of those who have been lost will remain in our hearts, and will serve only to strengthen the relationship between our two countries," Obama wrote. "May God bless the people of Japan."

In his White House appearance, Obama touched briefly on the recommendation by U.S. officials yesterday that American citizens evacuate beyond a 50-mile radius of the Fukushima Daiichi facility. That distance is five times farther from the crippled Japanese plant than the evacuation zone established by the Japanese government.

Obama said that decision was "based on a careful scientific evaluation" and on guidelines that the United States would use if the situation were occurring in the United States.

Since that order, some have wondered if the United States is undermining the Japanese government's disaster response by issuing different evacuation orders.

Obama said U.S. citizens in Japan should "continue to carefully monitor the situation and follow the guidance of the U.S. and Japanese governments. And those who are seeking assistance should contact our embassy and consulates, which continue to be open and operational."