But some said Israel's strike threat is not mere posturing.
Israeli and U.S. politicians have been bandying about the prospect of an airstrike on Iranian nuclear facilities, stirring fear that another destabilizing clash could be provoked in a region already rife with civil war in Syria and other religious and political tensions.
But nonproliferation experts and Middle East analysts are skeptical of Israeli claims that the Tehran regime is so close to building a nuclear weapon that time is running out for a peaceful resolution of the decades-long standoff.
"This is a window that has been closing for 15 years now, and it's always imminently about to close," said Jamal Abdi, policy director for the National Iranian American Council. He sees the sudden flurry of diplomacy between Jerusalem and Washington as an outgrowth of the U.S. presidential campaign and Israeli interest in ensuring that the United States continues to hold a hard line against Iran.
Recent high-profile visits by Defense Secretary Leon Panetta and presumptive Republican presidential candidate Mitt Romney gave a platform to Prime Minister Benjamin Netanyahu to proclaim Israeli impatience with diplomacy and sanctions, which he claimed had "not set back the Iranian program by one iota." Netanyahu put Panetta on notice that Israel is prepared to act alone in attacking Iran if it perceives itself to be at risk.
Alon Ben-Meir, a professor of international relations at New York University's Center for Global Affairs, said Netanyahu and Israeli Defense Minister Ehud Barak used the visits to send a message to Tehran that Israel won't hesitate to take unilateral action.
Ben-Meir cautions against seeing the Israeli threats as mere posturing, pointing out the profound national security concerns that shape Israeli defense policy. "I don't think Israel is bluffing entirely. There is an element of exaggerating its readiness to act and likelihood of winning. But many advisers to Prime Minister Netanyahu are saying that if he waits six or eight months, they may end up unable to do anything significant in terms of damage" to nuclear facilities that Iran has been moving underground to protect them from airstrikes, Ben-Meir said.
Veteran analyst said talks between U.S. and Israeli officials are focused on a possible "insurance policy" for Israel: U.S. bombs capable of penetrating and destroying underground facilities.
Threats of military action are spurred by Israel's frustration with the paltry progress of negotiations between Iran and six major powers. The talks are aimed at ensuring that Iranian programs are limited to peaceful purposes, said Gaukhar Mukhatzhanova, a nonproliferation scholar at the Monterey Institute of International Studies. "I don't see any particular breakthroughs in the Iranian program," she said, adding that, as far as preemptive air strikes were concerned, "there is technically no urgency to do this."