JERUSALEM, Jan. 12 (Xinhua) -- Washington is preparing to undertake any measure to thwart Iran's nuclear program, the U.S. ambassador to Israel Dan Shapiro said in an interview with the Hebrew-language Ma'ariv daily.
"We've said and I say again that all options are open ... President (Barack) Obama clearly and consistently says that he will do everything and resort to all necessary means to prevent Iran from producing nuclear weapons, and he means every word," Shapiro said, according to excerpts from the interview that will be published in full on Friday.
Shapiro underscored that the United States and Israel see eye- to-eye on the threat posed by Iran's nuclear ambitions.
"It is clear that for Israel it's an existential threat. It is also a threat to other states in the region, to Persian Gulf states and to America and its forces in the region," the newspaper quoted Shapiro as saying.
Top U.S. officials, among them Defense Secretary Leon Panetta, have publicly voiced their concern that Israel may attempt to independently strike Iran's nuclear facilities without informing the United States of its plans.
Shapiro said that "everyone agrees, including Israel, the U.S. and Europe" that economic sanctions are "the best way" to convince Iran to abandon its nuclear program.
"It should be made clear to the Iranian regime that it has to choose between realizing its nuclear program and preserving the country's economic existence," Shapiro told Ma'ariv.
He acknowledged, however, that though the United States has " upped the pressure (on Iran) to its highest level ever" with a fresh round of sanctions announced in December, "it is clear that their goal has not yet been obtained."
Asked what will happen in case the sanctions ultimately fail to yield results, Shapiro said that the Obama administration is " actively reviewing all options and drafting the necessary plans to ensure that all those options exist. The president hasn't ruled out any possibility."
The ambassador, who previously served on the House Foreign Affairs Committee and the National Security Council, declined to comment on whether the U.S. military is rehearsing plans to strike Iran's nuclear facilities, allowing only that "America doesn't require too much training. We already have a massive military presence in Gulf, don't we?"
Shapiro's remarks come a day after an explosion killed Mostafa Ahmadi-Roshan, a university professor of Iran and top nuclear scientist who supervised a department at the Natanz uranium enrichment facility in Isfahan province.
Roshan joined a long list of senior Iranian scientists who were assassinated in a similar fashion since January 2010, alongside a string of explosions at Iranian nuclear facilities that forced their temporary shutdown.
On Tuesday, Israel's military chief Lt.-Gen. Benny Gantz told parliament's foreign affairs and defense committee that "unnatural things" were happening in Iran, hinting that Israel and other western states were clandestinely sabotaging Tehran's nuclear program.