and could quickly produce a bomb, experts said. Fordo, they added, is Israel's most formidable impediment to halting Iran's nuclear program altogether.
As Israel continued attacking Iran, Michael Leiter, Israel's ambassador to the United States, confirmed his country's intention to target the site.
"The entire operation," he told Fox News in an interview, "really has to be completed with the elimination of Fordo."
Here is what we know about the site:
The facility, buried deep underground in a mountain in the village of Fordo, is roughly 20 miles from the holy city of Qom. While it is likely that construction on the plant began as early as 2006, the existence of the facility was publicly revealed in 2009.
Fordo is a uranium enrichment facility where Iran has developed centrifuges to process weapons-grade uranium up to 60% purity, an amount far higher than the 3.7% purity levels needed for civilian use.
The site was built to hold roughly up to 3,000 centrifuges, which spin quickly to produce fuel for nuclear weapons or reactors, said Richard Nephew, an Iran expert at the Columbia University Center on Global Energy Policy.
Iran, he said, had planned to install even more advanced centrifuges, called IR6s, that could process uranium three to five times more efficiently than the technology currently at the facility.
Considering the facility's size and configuration, Nephew said it was well-suited to producing weapons.
"If you don't deal with Fordo," Nephew said, "it's got enough centrifuges that it could produce a nuclear weapon pretty quickly,"
While it is not exactly clear who manages operations at the facility, experts said it was likely that a combination of the Iranian Atomic Energy Organization, the military and scientists at the plant were in charge.
The security around the facility is maintained by the Islamic Revolutionary Guard Corps, Nephew said.
Given the facility's location and fortifications, it would be difficult for Israel to penetrate it with traditional strikes, said Daniel Shapiro, a security expert at the Atlantic Council.
Compared to Natanz, the largest Iranian nuclear facility, which Israel struck early Friday, Fordo is much less exposed. Its destruction would require much more specific bunker-busting equipment.
"If you were to just sort of drop bombs on it, it wouldn't penetrate it," Nephew said.
However, even if Israel doesn't breach the parts deepest underground, it still may be able to make Fordo inaccessible, by destroying the entrance to it.
Experts agreed that a plan to disable the site -- perhaps a combination of special and covert operations, they said -- would be essential to stopping Iran's nuclear program.
"The Israelis have got a multiday campaign plan," Nephew said. "It is inconceivable to me that Israelis would launch this attack without an idea of how to deal with Fordo."
This article originally appeared in The New York Times.
