Early signs suggest that the Israeli attack did not penetrate the protective layer protecting Iran's nuclear storage facility, Internet reported. The International Atomic Energy Agency (IAEA) said there were no signs of increased radiation levels at Iran's main uranium enrichment facility. Iranian authorities told the International Atomic Energy Agency they had not observed higher radiation at the Natanz facility, about 300 kilometers south of Tehran. Israeli authorities say Israel has not carried out any attack on Iran's Bushehr nuclear power plant on the Persian Gulf coast. Still, Israeli Prime Minister Benjamin Netanyahu said the attack "will last for a few days until the threat is eliminated." Only the most powerful conventional munitions can penetrate Iran's uranium enrichment facilities. The Natanz nuclear facility is built more than 40 meters underground and is protected by a reinforced concrete shell. Researchers estimate that the shell is about 8 meters thick. At the Fordo nuclear facility, the enrichment hall is built in the mountains. After a recent visit to the International Atomic Energy Agency Director General Grosi estimated that the uranium enrichment hall is located half a kilometer underground. (Jin Shi)