The White House is preparing for a situation in Japan that could be "deadly for decades," a U.S. official tells ABC News.
According to the official, the U.S. believes a larger evacuation zone should be imposed and that the next 24-48 hours are "critical."
"It would be hard to describe how alarming this is right now," ABC quoted the anonymous official as saying.
The nuclear crisis in Japan has intensified since the massive earthquake first damaged nuclear facilities. On Wednesday, the White House advised Americans within 50 miles of the Fukushima nuclear facility to evacuate and plant employees were temporarily forced to retreat as radiation levels "soared."
The difficulties caused by the evacuations were blamed for "escalating" the chances of a meltdown.
"They need to stop pulling out people -- and step up with getting them back in the reactor to cool it. There is a recognition this is a suicide mission," the unnamed U.S. official was quoted by ABC as saying.
The U.S. Nuclear Regulatory Commission's chief claimed there is no water in one of the spent fuel pools at the Fukushima nuclear plant, which Japanese officials have denied. According to the AP, "If NRC Chairman Gregory Jaczko is correct, this would mean there's nothing to stop the fuel rods from getting hotter and ultimately melting down." White House spokesman Jay Carney said on Wednesday that the situation in Japan is "deteriorating and fast-moving."
Cables recently released by WikiLeaks show the Japanese government was warned about the design of its nuclear reactors years ago, and did not act.