Radiation reached around 20 times normal levels in the capital Tuesday morning, the Tokyo Metropolitan Government said, while offering the assurance this reading posed no immediate risk to human health and that the public should remain calm.
"I received a report this morning that there was an important change of data," Gov. Shintaro Ishihara said at a news conference. "I heard that it will not immediately cause health problems."
He said the metropolitan government would continue to give minute-by-minute updates.