Israel is engaged in a covert war against Iran's nuclear program, London's Daily Telegraph quoted US intelligence sources as saying on Tuesday, in an effort to disrupt its nuclear efforts without direct military intervention that could prompt a wider war. Sabotage, the use of front companies and double agents, as well as the assassination of top figures involved in Iran's atomic operations, were all being pursued to try to interrupt the program, the paper reported. "Disruption is designed to slow progress on the program, done in such a way that they don't realize what's happening. You are never going to stop it," a former CIA officer with expertise on Iran told the Telegraph. "The goal is delay, delay, delay until you can come up with some other solution or approach. We certainly don't want the current Iranian government to have those weapons. It's a good policy, short of taking them out militarily, which probably carries unacceptable risks." The paper said Israeli officials privately acknowledge that the new US administration is unlikely to sanction an air attack on Iran's nuclear installations and that President Barack Obama's "offer to extend a hand of peace" to Teheran has rendered direct military action out of the question for the time being. In an interview with The Jerusalem Post earlier this month, by contrast, former US ambassador to the UN John Bolton stressed that Israel might well have to "go it alone" militarily against Iran, whatever the US attitude. "It has done so in the past," Bolton noted. "For example, it undertook the very important operation, in September 2007, to destroy the North Korean nuclear reactor in Syria. That was done, if not over US opposition, certainly without US approval." Bolton said there was no likelihood of American use of force against Iran, and "that leaves Israel. "Of course, the military option is a very unattractive one," he said. "It's risky. You could end up with the worst of both worlds: taking action without breaking Iran's control over the nuclear fuel cycles, and yet incurring the disapproval of governments all over the world. But you have to have the military option front and center, because the alternative is far more unattractive." The Telegraph article comes on the heels of a spate of reports about purported sabotage efforts. In his book The Secret War with Iran, published last September, for instance, Israeli journalist Ronen Bergman listed a series of sabotage operations that had prevented Iran from being even closer still to the bomb. These included the case of a leading expert on electromagnetics who worked at Iran's Isfahan enrichment facility being found dead at his home in 2007, and reports of an explosion at his laboratory; three or four planes crashing inside Iran in 2006 and 2007 with personnel connected to the security of the nuclear project on board; insulation units for the centrifuge enrichment process discovered to be unusable; and various explosions caused by faulty equipment at the main Natanz facility and at Isfahan, including the wrecking of 50 centrifuges when two transformers blew up at Natanz in 2006. The last of these incidents was attributed by Bergman to "efforts implemented jointly with the United States." Overall, Bergman wrote, "Since Meir Dagan became Mossad director in 2002, Israel has significantly improved its knowledge about goings-on inside Iran, and has even taken certain preemptive actions." Nonetheless, that book and other published material in recent months have given the impression that Iran has essentially cleared its technical hurdles, and is into the home stretch - racing against the clock to get the bomb before international pressure, of whatever kind, forces a halt. In its story on Tuesday, the British newspaper quoted Reva Bhalla, a senior analyst at Stratfor, a US private intelligence company with strong government security connections, as saying that the Israeli strategy was also to assassinate key figures. "With cooperation from the United States, Israeli covert operations have focused both on eliminating key human assets involved in the nuclear program and in sabotaging the Iranian nuclear supply chain," she said. "As US-Israeli relations are bound to come under strain over the Obama administration's outreach to Iran, and as the political atmosphere grows in complexity, an intensification of Israeli covert activity against Iran is likely to result." The paper went on to cite a rumor that the Mossad was responsible for the death of Ardeshire Hassanpour, the top nuclear scientist at Isfahan mentioned by Bergman, who it said reportedly died from gas poisoning. It also mentioned other recent deaths of figures connected to Iran's nuclear program that were reportedly the result of Israeli hits. "Israel has shown no hesitation in assassinating weapons scientists for hostile regimes in the past," the paper quoted an anonymous European intelligence official as saying. "They did it with Iraq and they will do it with Iran when they can." The former CIA operative also revealed to the Telegraph how Israeli and US intelligence cooperated with European companies working in Iran to obtain photographs and other confidential material about Iranian nuclear and missile sites. "It was a real company that operated from time to time in Iran and in the nature of their legitimate business came across information on various suspect Iranian facilities," he said. Israel, the report added, had also apparently used front companies to infiltrate the purchasing network used by Iran to get around United Nations sanctions and attain so-called "dual use" items - metals, valves, electronics, machinery - for its nuclear program. It said these front companies first supply legitimate material, winning Teheran's trust, before delivering faulty or defective items that sabotage the country's atomic activities. Mossad and Western intelligence operations have also infiltrated the Iranian nuclear program, "bought" information from prominent atomic scientists and leaked details to its allies, the media and United Nations atomic agency inspectors, the paper went on to say. On one occasion, said the report, Iran destroyed a nuclear facility near Teheran after its existence was revealed to UN inspectors, fearing overwhelming UN pressure for tougher action. The paper added that Iran had become so concerned about penetration of its program that it has announced arrests of alleged spies in a bid to discourage double agents. Former CIA counter-terrorism chief Vince Canastraro, however, doubted the effectiveness of the alleged covert operations. "You cannot carry out foreign policy objectives via covert operations," he told the British newspaper. "You can't get rid of a couple of people and hope to affect Iran's nuclear capability."