The surprise assessment stunned many in Israel, which has relied on the United States for support of the view that Iran constitutes a grave strategic threat.
Responding to the apparent newly opened gap in Israeli and U.S. assessments of Iran's nuclear program, Israeli Prime Minister Ehud Olmert tried to sound upbeat.
The intelligence report, Olmert told reporters Tuesday, at least confirmed that Iran recently had designs for an offensive nuclear capability. Olmert also pointed out that the report concluded that Iran's current uranium enrichment program still has the potential to produce material for warheads between 2010 and 2015.
"It's crucial to pursue efforts to prevent Iran from developing a capability like this, and we will continue doing so along with our friends the United States," Olmert said.
Olmert has endorsed U.S.-led efforts to curb Iran's atomic aspirations through sanctions, but both he and U.S. President George W. Bush have warned that pre-emptive action could be used as a last resort to stymie Iran's nuclear capability.
Israeli Defense Minister Ehud Barak was markedly less sanguine than Olmert, giving an interview this week in which he effectively accused the Americans of faulty intelligence gathering.
"It's true, it seems that Iran froze its nuclear program in 2003," Barak told Army Radio. "But as far as we know it has since renewed its program."
Barak suggested that U.S. and other intelligence services were "disconnected" from goings-on in the Islamic Republic.
Infrastructure Minister Benjamin Ben-Eliezer, a former defense chief, dismissed the report's findings this way: "I don't buy it."
The ministers' comments reflected the deep skepticism in Israel and elsewhere around the world about the quality of U.S. intelligence assessments, particularly given the failure of U.S. intelligence in the lead-up to the invasion of Iraq.
Israeli experts said the 16 intelligence agencies in the United States likely were playing it safe following the CIA's erroneous assessment that the 2003 invasion of Iraq would uncover Saddam Hussein's secret weapons-of-mass-destruction program.
"Back then, the absence of hard information led the Americans to adopt a worst-case approach," said a retired Israeli intelligence analyst who declined to be named. "Nowadays the thinking is to favor inaction in the absence of hard information."
Amid all the bluster in Israel, there was no sign of past Israeli threats to go it alone against Iran if necessary.
"Israeli officials are afraid that the report is liable to reduce international pressure on Iran," Alex Fishman wrote in the Israeli daily Yediot Achronot.
"If the issue is a nuclear Iran in only another five or six years -- and even that is contingent upon the Iranians renewing their military nuclear program -- then there is no legitimacy for dealing Iran a military blow in the near future. That means that the military strike is off the table," he wrote. "And the urgency for sanctions against Iran is liable to decrease as well."
Israel still could mount a sneak attack as it did in Iraq in 1981, destroying Saddam's nuclear reactor in Osirak. But many foreign analysts have questioned whether Israel's seasoned yet relatively small air force could tackle Iranian nuclear sites that are distant, multiple, dispersed and well fortified.
Nevertheless, some Israeli officials cite Israel's Sept. 6 airstrike in northern Syria, which was widely reported to have targeted a nascent reactor, as an encouraging precedent.
"If the reports are true, then our jets managed to slip in and out of Syria with little incident," one Israeli diplomat said. "That would suggest a degree of sophistication that makes even Iran a feasible target, should it come down to that."