Teheran probably has the material necessary to make a nuclear weapon, Adm. Mike Mullen, the chairman of the US Joint Chiefs of Staff, said on Sunday, while Secretary of Defense Robert Gates said the Iranians were not yet close to attaining a weapon. Asked on CNN if Teheran had enough nuclear material for the construction of an atomic bomb, Mullen said: "We think they do, quite frankly." "Iran having a nuclear weapon, I believe, for a long time, is a very, very bad outcome for the region and for the world," he said. Gates, speaking on NBC's Meet the Press, seemed to say just the opposite. "They're not close to a stockpile, they're not close to a weapon at this point, and so there is some time," he said when asked whether the Islamic republic could be deterred from pursuing nuclear weapons. The US would continue to pursue additional sanctions, while also leaving an opportunity for Iran to engage with Europe as a means to "walk away from that program," Gates said. The UN's International Atomic Energy Agency said last week that it had been wrong in earlier reports and now had evidence that Iran has enough enriched uranium to make a nuclear weapon. An Israeli official said the admission now by Mullen that Teheran probably had enough material for a nuclear bomb strengthened those who have long believed this, adding that US officials had not wanted to say this in public so as not to give former president George W. Bush a pretext for military action. "One has to ask why all this is coming out now, and not a couple months ago," the official said. Neither the Prime Minister's Office nor the Foreign Ministry had a response to Mullen's comments. The US commander's remarks came several days after a research institute said the Islamic republic had enough uranium for a nuclear bomb. The Washington-based Institute for Science and International Security said in a report that Iran had reached "nuclear weapons breakout capability." The report followed an analysis of information from the IAEA. However, an IAEA official warned against drawing such dramatic conclusions from the data, saying that to qualify as weapons-grade material, Iran's stash of low-enriched uranium would have to be transformed into highly enriched uranium, which has yet to be done. Last week, Iran's nuclear chief, Vice President Gholam Reza Aghazadeh, announced that 6,000 centrifuges were now operating at the enrichment facility in Natanz. He said Teheran hoped to install more than 50,000 centrifuges there over the next five years. "We are doing what we need to do in Natanz on the basis of a specific time schedule," he told a press conference. Iran says it intends to use the enriched uranium fuel in its first domestically-built nuclear power plant in Darkhovin, which it wants to start operating in 2016. Aghazadeh said any delay in enrichment would mean a delay in opening Darkhovin. The plant, which will run on enriched uranium imported from Russia, has worried the West because the spent fuel could be turned into plutonium for nuclear warheads. With the amount of centrifuges it is using in the enrichment process, Iran could add about 100 kg. of uranium to its stockpile each month, or even more, considering that it is setting up additional ready-to-go centrifuges every day. Even 100 kg. would give it an estimated low-enriched uranium stockpile of just over 1,100 kg. - the minimum experts believe is required to yield the 25 kg. of highly enriched weapons grade uranium needed to build a bomb. Defense Minister Ehud Barak said on Wednesday that that day's test run at Bushehr and Iran's claims that it had increased the number of centrifuges to 6,000 constituted an existential threat to Israel. "Israel's policy is clear: We are not ruling out any option regarding the Iranian nuclear [program] and we recommend that others don't rule out any option either," he said in an address at the Interdisciplinary Center, Herzliya, in a hint to US President Barack Obama's administration. "A dialogue with Iran should be defined and limited in time," Barak said. "Time is running out. Clear and decisive sanctions against the Iranian regime, alongside readiness to consider necessary actions in case the sanctions don't work, are necessary," Barak said. He added that Russia has had a crucial role in pressuring Iran, and that sanctions without Russia's participation would be meaningless. Yaakov Katz and Jerusalem Post staff contributed to this report.