Jerusalem--Israeli Prime Minister Benjamin Netanyahu called on Monday for an immediate embargo on Iran's energy sector, saying the UN Security Council should be sidestepped if it cannot agree on the move. Iran's uranium enrichment in defiance of several rounds of Security Council sanctions has spurred world powers to consider tougher measures to halt what the West fears is a drive to produce nuclear weapons. Israel has endorsed the talks while hinting at preemptive military action should it deem diplomacy a dead end. If the world "is serious about stopping Iran, then what it needs to do is not watered-down sanctions, moderate sanctions ... but effective, biting sanctions that curtail the import and export of oil into Iran," Netanyahu said in a speech. "This is what is required now. It may not do the job, but nothing else will, and at least we will have known that it's been tried. And if this cannot pass in the Security Council, then it should be done outside the Security Council, but immediately." Though it is the world's fifth-largest oil exporter, Iran imports some 40 percent of its gasoline from foreign refineries. Many Western diplomats believe that China, along with fellow veto-wielder Russia, would block any Security Council sanctions targeting Iran's energy sector. Proposed sanctions for now focus on Iranian government assets like the Revolutionary Guard Corps. Netanyahu spokesman Mark Regev said Israel would prefer the Security Council to curb Iran but believed there was enough international support outside that forum for energy sanctions. "If the United States, Europe and like-minded countries act in unison, they can succeed in sending the desired message and forcing the regime in Tehran to rethink its nuclear weapons programme," Regev said. Israel's Haaretz daily reported in 2008 that Netanyahu's predecessor, Ehud Olmert, proposed for the United States to enforce a naval blockage on Iran. Regev declined to discuss whether the current Israeli government had similar ideas. Netanyahu has in the past predicted energy sanctions would be enough to "cripple" Iran. He appeared to demur on Monday by raising the prospect that Iran -- which announced plans to build two new enrichment plants -- could weather even an oil embargo. Regev said the premier was speaking extemporaneously in his English address to diaspora Jewish leaders, and that there was no change to Israel's strategic view on its arch-foe. Iran says its uranium enrichment is for energy or medical needs, but Tehran's anti-Israel rhetoric and support for Islamic guerrillas on the Jewish state's borders, as well as concerns over an Israeli military strike, have stirred fears of conflict. Netanyahu made no reference to the possibility that Israel, which is assumed to have the Middle East's only atomic arsenal, would try to attack Iran's nuclear facilities. Some analysts believe this option is circumscribed by the long ranges, Iranian defenses, and US reluctance to see another regional conflict.