6:23 PM EST
TOKYO -- A meltdown may be under way at one of Fukushima Daiichi's nuclear power reactors in northern Japan, an official with Japan's Nuclear and Industrial Safety Agency told CNN Sunday.
"There is a possibility, we see the possibility of a meltdown," said Toshihiro Bannai, director of the agency's international affairs office, in a telephone interview from the agency's headquarters in Tokyo. "At this point, we have still not confirmed that there is an actual meltdown, but there is a possibility."
Though he said engineers have been unable to get close enough to the core to know what's going on, he based his conclusion on the fact that they measured radioactive cesium and radioactive iodine in the air Saturday night.
"What we have seen is only the slight indication from a monitoring post of cesium and iodine," he said. Since then, he said, plant officials have injected sea water and boron into the plant in an effort to cool its nuclear fuel.
We have some confidence, to some extent, to make the situation to be stable status," he said. "We actually have very good confidence that we will resolve this."
A state of emergency has been declared for it and two of the other five reactors at the same complex, he said. Three are in a safe, shut-down state, he said. "The other two still have some cooling systems, but not enough capacity."