While sanctions against Iran are visibly impairing its economy, they have not impacted its continuing nuclear activities, Prime Minister Binyamin Netanyahu told CNN in a Tuesday interview."They're certainly taking a bite out of the Iranian economy, but so far they haven't rolled back the Iranian program or even stopped it by one iota," Netanyahu said. "I hope that changes, but so far, I can tell you the centrifuges are spinning." Reuters contributed to this report"If the sanctions are going to work, they better work soon," he emphasized.Asked how he knows about Iran's nuclear activities, the prime minister coyly retorted, "Oh, we know." "We know, and others know and we share what we know. This is not a case of the questions that people had about Saddam Hussein," he continued when pressed further, referring to the botched intelligence on Iraq's nuclear program ahead of the 2003 invasion.Sanctions forced Iran to deploy more than half its fleet of supertankers to store oil at anchorage in the Gulf as buyers of its crude cut back, two Iran-based shipping sources said Monday.The sources, who are familiar with operations at Iran's main export terminal Kharg Island in the north of the Gulf, said 14 of National Iranian Tanker Company's (NITC) fleet of 25 very large crude carriers, each loaded with about 2 million barrels of oil, are now at anchor acting as floating storage.A further five of Iran's nine Suezmax tankers, with capacity of one million barrels, are also parked offshore with oil aboard.That means that of Iran's 59-million-barrel fleet of VLCCs and Suezmax sized tankers, 33 million barrels of capacity are being used to store crude at sea in the Gulf, or 56 percent of the fleet.