Defense Minister Ehud Barak will fly to Washington tonight for more talks with senior U.S. officials on dealing with the Iranian nuclear threat.
Barak's visit will come less than a week before Prime Minister Benjamin Netanyahu arrives in the United States, where he is expected to meet with President Barack Obama in the White House.
Meanwhile, a report published Friday by the International Atomic Energy Agency (IAEA ) says Iran has increased its uranium enrichment in the fortified underground facility at Fordo, near the city of Qom.
Barak, who will be in the United States for less than two days, will meet with most of the senior U.S. administration other than Obama.
He is to have meetings with Vice President Joe Biden, Secretary of Defense Leon Panetta, and senior Pentagon and intelligence figures.
Last week, U.S. National Security Adviser Tom Donilon and Director of National Intelligence James Clapper were in Israel for talks dealing mainly with Iran.
The Americans see Barak as the Israeli government's right flank with regard to attacking Iran, and as having influenced Netanyahu's hawkish stance.
Officials in Washington dispute Barak's assessment that Tehran is on the verge of entering an "immunity zone" - a point at which Iran would be impervious to significant damage to its nuclear program because it will have enough centrifuges in an underground facility to continue enriching as much uranium as it likes.
According to the IAEA report, Iran has almost tripled its 20-percent enrichment of uranium in the facilities in Natanz and Fordo.
The Iranians now have about 5.4 tons of low-grade uranium which can be used in the future - after it is enriched to a high level of around 90 percent - to make four nuclear weapons. Iran also has 100 kilograms of uranium enriched to a level of 20 percent and is producing another 11 kilograms of such uranium every month.
However, the report also said the operation of the advanced centrifuges to enrich the uranium was having trouble and progressing more slowly than expected.
In contrast to the severe report, The New York Times reported Friday that, based on statements by senior American officials and former government nuclear scientists, there is still no clear-cut intelligence evidence that Iran has decided to manufacture nuclear weapons. Among the senior officials the Times quotes are Panetta and Clapper.
This assessment conforms to that of the Israeli intelligence community, as reported by Haaretz about a month ago.
Despite Iran's significant progress both in enriching uranium and in developing technologies for mounting a nuclear warhead on a long-range surface-to-surface missile, it appears that Tehran has not yet decided to cross another red line - actually manufacturing a nuclear weapon.
Israeli intelligence officials believe that this decision depends mainly on the Iranian spiritual leader Ayatollah Khamenei, and will be made based on a risk assessment involving the responses of the international community, the United States and Israel.
As far as Washington is concerned, the critical red line is the step to actual manufacturing of nuclear weapons. That is the achievement the United States would seek to prevent, either by ratcheting up sanctions or by "other means," an extreme scenario which would also include military action.
But the Times also quotes former administration officials who say there is no proof that Iran has renewed its progress on a nuclear weapons program, which was halted in 2003 when the United States went into Iraq. That claim appeared in an American intelligence report in late 2007, and was a point of contention between Washington and Jerusalem.
Sources in Israel say Tehran's military nuclear program is still underway, even if the decision itself has not been made to manufacture a bomb. In recent years the impression has been that this was also the U.S. position. However, the people that the Times quotes as espousing this idea are not currently serving officials.
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