President Barack Obama on Friday said the United States "stands ready to help the Japanese people in this time of great trial" after a magnitude-8.9 earthquake hit north-eastern Japan, DPA reported.
White House chief of staff Bill Daley informed Obama about the earthquake at about 4 am (0900 GMT).
"Michelle and I send our deepest condolences to the people of Japan, particularly those who have lost loved ones in the earthquake and tsunamis," a statement from Obama said.
"The United States stands ready to help the Japanese people in this time of great trial.
"The friendship and alliance between our two nations is unshakeable, and only strengthens our resolve to stand with the people of Japan as they overcome this tragedy," the statement added.