by Hiroyoshi Itabashi and Hidefumi Nogami

Between late on March 14, 2011, and early the next morning, a top secret diplomatic cable arrived at the Foreign Ministry. […]

“The United States has made various preparations to deal with the nuclear accident. The president is also very concerned,” the cable went on to say.

By invoking the White House, [Adm. Mike Mullen, chairman of the U.S. Joint Chiefs of Staff] impressed upon Japanese Embassy officials that not just the U.S. military but the entire U.S. government was worried about how the situation was developing. […]

At 7 a.m. [on March 15], a situation arose which the U.S. military is still keeping quiet about.

At Yokosuka Naval Base, which lies about 300 kilometers from the Fukushima No. 1 nuclear power plant, alarms went off indicating an increase in radiation levels. All women and children on the base were immediately ordered to evacuate. […]

U.S. government officials who were notified became very concerned because of the possibility that the Yokosuka Naval Base, considered of major strategic importance in East Asia, would become inoperable if the situation at the Fukushima plant worsened. […]