Netanyahu says Iran sanctions aren't working. His UN ambassador disagrees.

Who to believe?

Israeli Prime Minister Benjamin Netanyahu, as is his habit, sought to pour cold water over the notion that US-led international sanctions on Iran are having an effect on its controversial nuclear program.

Sure, the sanctions have undermined the Iranian currency, resulted in the expulsion of Iran's central bank from the international system that facilitates interbank transfers, and squeezed Iran's oil exports, the government's major revenue source. The rial has lost about 40 percent of its value against the dollar since December, and is now trading on the informal market at about 20,000 rials to the dollar. In the latest sign of the pain being inflicted on Iran's economy, a newspaper there today reports that the government has banned the import of 600 products.

But Mr. Netanyahu told reporters yesterday that he sees no evidence of any impact on Iran's calculations about its controversial nuclear program. Israel insists Tehran is seeking a nuclear weapon, but Iran says its program is for peaceful purposes only. (A report from the United Nations nuclear watchdog last fall estimated that Iran stopped the bulk of its weapons-related work around 2003, but continued some modeling and design work until 2009.) The Israeli prime minister also indicated that he hopes sanctions lead to regime collapse.

"The sanctions are painful, hard .. but will this bring about a halt or a retreat in the Iranian nuclear program? Until now, it has not happened," he said. The Iranian government "is struggling financially and it still hasn't turned back by even one millimeter from its nuclear program," he told reporters in Israel.

Not everyone agrees with Netanyahu, among them Ron Prosor, Israel's ambassador to the United Nations. On Friday, Ambassador Prosor told reporters that the sanctions have a good shot at changing Iran's behavior.

"I think the international community at this stage has really moved forward and have made at least clear to Tehran that there is a certain price tag for continuing," he said. "The decision on SWIFT [the global system for interbank transfers], the issue of the sanctions by the EU, are important and have an effect on Iran... I do see really a movement on the international stage, especially on the economic side.... It's much more effective than people think and it might change, hopefully it might change behavior patterns if we continue with it."

"SWIFT" is the Society for Worldwide Interbank Financial Telecommunication, which coordinates millions of secure communications and money transfer information between the world's banks every day. Last month, Iran was unplugged from the system in a highly unusual move, creating major obstacles for the country's banks, including the central bank.

Netanyahu has consistently insisted that Iran is moving implacably toward a nuclear weapon and characterized the country as an existential threat to the Jewish state, leading to speculation that he may decide to unilaterally attack Iran.

Recently there have been some hints, however, that Israeli's defense establishment is backing away from talk about attacking Iran, particularly as the Obama administration has sought to cool the war talk to give sanctions a chance to work. A story in the hawkish Jerusalem Post yesterday, for instance, reported that "a possible military confrontation with Iran may be postponed until 2013, senior defense officials said in recent weeks amid growing signs that the West’s economic crackdown on Iran is bearing fruit."

Currently the only nuclear power in the Middle East is Israel, with a minimum of 100 warheads.