on CNN website (2011/03/16):
[3:01 p.m. ET Wednesday, 4:01 a.m. Thursday in Tokyo] Concerned about potential radiation exposure, the U.S. military will not allow troops to get within 50 miles of the damaged Fukushima Daiichi nuclear plant, Col. David Lapan, a Pentagon spokesman, says.
Earlier, the U.S. Embassy in Tokyo said it was recommending as a precaution that Americans who live within 50 miles (80 kilometers) of the plant evacuate or take shelter indoors. This is a break from the recommendation by the Japanese government, which has told people at least 20 miles away from the damaged reactors to evacuate.
Before Wednesday, the United States had urged American citizens in Japan to follow the recommendations of the Japanese government. The new U.S. recommendation "suggests that the advice the Japanese government is giving based on the information it has is different than the advice we'd be giving if this incident happened in the United States," White House spokesman Jay Carney told reporters.