There were no reports of damage to the aircraft carrier USS George Washington, which was in port in Japan. In Guam, the mooring lines of two US navy submarines broke free of the pier, but there was no damage and the ships were pushed back by tugs.
No ships have been moved as a result of the potential tsunami in Hawaii.
Vice President Joe Biden, making a joint appearance at a news conference in Chisinau, Moldova Friday with Prime Minister Vlad Filat, said "the thoughts and prayers of the American people" are with the Japanese, who he said had suffered through a "mega earthquake."
"We, the United States, stand ready to do anything we can to help our Japanese friends as they deal with the aftermath of this tragedy," Biden said.