Reuters A UN report that Iran worked to develop an atomic bomb design is likely to trigger more Western sanctions and give impetus to a suspected covert campaign by the West and Israel to sabotage Tehran's nuclear activities. But any unilateral Western curbs will probably stop short of sweeping extra steps on Tehran's lifeline energy sector for fear of damaging the global economy and backfiring politically on Western governments struggling to stave off recession. And chances are slim of stiffer United Nations sanctions, potentially the most effective type as they bind the whole of the international community, because Tehran's traditional sympathisers Russia and China have the power to veto any council resolution to tighten sanctions . For those two countries to throw their weight behind additional tough UN measures, analysts say, the UN report would probably have had to provide incontrovertible “smoking gun” evidence of a current program to build a nuclear weapon. Instead, the International Atomic Energy Agency (IAEA) report, although widely seen as its most damning to date and citing “serious concerns about possible military dimensions to Iran's nuclear program”, was less categorical. Its main finding was that Iran appeared to have worked on designing a nuclear warhead and that secret weapons-relevant research may be continuing. The Obama administration, pressured by the US Congress, will now likely push for tougher sanctions, said Trita Parsi, president of the National Iranian American Council, a moderate public interest group. “But the bottom line is that, while a new package of sanctions targeting the nuclear program may help slow down the program, it is unlikely to change its trajectory,” he said. “Indiscriminate sanctions that harm the Iranian people rather than the government ... will only make matters worse,” he said, referring to economic strains experienced by ordinary Iranians . “To resolve the problem, sustained and persistent diplomacy is needed. But diplomacy is a tough road to travel, because it requires more political capital and will than sanctions do.” The IAEA report lent support to analysts who suspect Tehran is developing the ability to weaponize its nuclear material in the event it ever decided to build a bomb. But it offered little concrete backup for who those fear Iran is rushing to develop nuclear weapons, or to those at the other end of the spectrum of opinion who say assurances that Iran's nuclear work is solely peaceful should be believed. Iran's nuclear advance may have been slowed by sanctions, suspected sabotage such as the Stuxnet computer virus and covert interception of Iranian nuclear smuggling. __