The State Department is advising U.S. citizens to avoid traveling to Japan at this time.
The Asian nation, a close American ally, was struck by devastating earthquakes, a deadly tsunami and is now threatened by possible radiation leaks from several nuclear reactors damaged in the natural disaster. Japan's prime minister says his country is facing its worst crisis since the end of World War II.
In a travel alert issued Sunday, the State Department is urging all non-essential U.S. government personnel to forego travel to Japan. The Department also says Americans should avoid tourism and other unnecessary visits to Japan for now.