WASHINGTON – US Treasury Secretary Jack Lew defended the Obama administration’s diplomacy with Iran on Sunday, vowing to continue enforcing harsh sanctions against the Islamic Republic until world powers reach a comprehensive solution definitively ending the nuclear crisis.Entering historic negotiations in Vienna, the US delegation is prepared to accept a limited nuclear program in Iran that “is, and will remain, exclusively peaceful,” Lew said in his speech to the American Israel Public Affairs Committee’s annual policy conference on Sunday night.“This is not a case of ‘trust’ but ‘verify,’” Lew said. “It is a case of ‘verify everything.’” In the meantime, the Treasury Department – which enforces US sanctions law – will continue to enforce “the most sweeping, the most powerful and the most innovative” financial penalties in history, Lew said.“Today, for the first time in a decade, progress on Iran’s nuclear program has been halted,” he said. “The vast majority of our sanctions remain firmly in place.”An interim deal reached between Iran and the P5+1 – the US, UK, France, Russia, China and Germany – granted Iran roughly $7 billion in sanctions relief in exchange for an effective freeze over much of their nuclear work, while the parties attempt to negotiate a final nuclear agreement.During the six-month duration of that interim deal, Iran will lose $30 billion in oil revenues alone from continued economic sanctions, Lew said.Characterizing the Iranian economy as “leveling off at the bottom of a recession,” the Treasury head said critics of the deal were “just plain wrong” in asserting that Iran’s economy was recovering during the deal, formally known as the Joint Plan of Action.Iran has a 30 percent inflation rate, one of the highest in the world. “We are well aware that businesspeople have been talking to the Iranians,” he conceded, insisting that the US would response with severe penalties “with speed and force.”Lew said he had stood by the side of two US presidents as they weighed the deployment of American armed forces. He noted that the US had sent Iran the “very clear signal” that new sanctions would be enforced if diplomacy fails – and that military action would be considered, as well, in order to block Iran from obtaining nuclear arms.“If the moment comes when we have to use force, the world has to understand that we’ve done everything to pursue diplomacy,” he said.That international consensus, Lew added, has been key in making sanctions more effective.“No amount of US sanctions would have the same crippling power as has this international effort,” Lew said.