By Patricia Zengerle and David Morgan
WASHINGTON (Reuters) - President Barack Obama sent condolences to the people of Japan on Friday and said the United States stood ready to help its close ally after a massive earthquake and tsunami.
The U.S. Defense Department was preparing American forces in the Pacific to provide relief after the quake, which generated a tsunami that headed across the Pacific Ocean past Hawaii and toward the west coast of the U.S. mainland.
The U.S. Air Force transported "some really important coolant" to a Japanese nuclear plant affected by the quake, Secretary of State Hillary Clinton said.
Authorities said at least hundreds of people were killed in Japan and the toll is expected to rise.
"The friendship and alliance between our two nations is unshakable, and only strengthens our resolve to stand with the people of Japan as they overcome this tragedy," Obama said in a statement.
Obama, who called Japanese Prime Minister Naoto Kan on Friday morning and was being briefed on the disaster, is set to give a news conference at 12:30 p.m. EST (1730 GMT).
His chief of staff, Bill Daley, awakened the president to tell him about the earthquake at about 4 a.m. EST (0900 GMT).
Daley told a meeting of the President's Export Council it appeared Hawaii was spared serious impact from the tsunami.
There is still some risk to the U.S. West Coast "but I think the enormous fears that were there hours ago, for some of us hours ago, have diminished greatly, which is quite a relief for all of us," he said.
U.S. NAVY SHIPS
The U.S. military effort included at least six Navy ships, although defense officials had not yet received a request for assistance from the Japanese government, Pentagon spokeswoman Navy Commander Leslie Hullryde said.
"We are positioning our forces so we are ready to respond and provide disaster relief, if requested," she said.
Senate Foreign Relations Committee Chairman John Kerry vowed full U.S. support for the key military ally.
"First responders and military forces from Japan and the United States train regularly to react to natural disasters, and just as we have worked together to aid countries such as Burma, Indonesia, and the Philippines, we will spare no effort now as rescue and recovery operations get underway in Japan," Kerry said in a statement.
The State Department said U.S. embassy operations in Japan were moved from Tokyo to another location as a precaution.
There have been no reports of Americans killed or injured in the quake. A State Department travel alert strongly urged Americans to avoid nonessential travel to Japan.
"Strong aftershocks are likely for weeks following a strong earthquake such as this one," it said.
The State Department said it was setting up an email address and telephone number to handle inquiries from people with relatives in Japan.
(Editing by Will Dunham)