NEW YORK - Despite all the speculation - mostly generated by Israel - about Iran’s nuclear ambitions, US intelligence analysts believe that there is still no hard evidence that Iran has decided to build an atomic bomb, according to American media reports.

A highly classified US intelligence assessment circulated to policymakers early last year largely affirms that view, originally made in 2007, the reports said. Both reports, known as national intelligence estimates, conclude that Tehran halted efforts to develop and build a nuclear warhead in 2003.

Citing current And former American officials, the New York Times said that assessment was largely reaffirmed in a 2010 National Intelligence Estimate, and that it remains the consensus view of America’s 16 intelligence agencies.

“At the centre of the debate is the murky question of the ultimate ambitions of the leaders in Tehran,” the NYT said. “There is no dispute among American, Israeli and European intelligence officials that Iran has been enriching nuclear fuel and developing some necessary infrastructure to become a nuclear power. But the Central Intelligence Agency and other intelligence agencies believe that Iran has yet to decide whether to resume a parallel programme to design a nuclear warhead - a programme they believe was essentially halted in 2003 and which would be necessary for Iran to build a nuclear bomb.”

Iranian officials maintain that their nuclear programme is for civilian purposes, not weapon-oriented.

But Israel regards Iran as a threat to its existence and says it will not allow Iran to become capable of building and delivering a nuclear weapon, The Los Angeles Times, another national newspaper, pointed out. Some Israeli officials have raised the prospect of a military strike to stop Iran before it’s too late. “It’s unclear how much access US intelligence has in Iran, a problem that bedevilled efforts to determine whether Iraq had weapons of mass destruction before the U.S.-led invasion in 2003,” the LA Times said.

In Senate testimony on January 31, James Clapper, the director of national intelligence, stated explicitly that American officials believe that Iran is preserving its options for a nuclear weapon, but said there was no evidence that it had made a decision on making a concerted push to build a weapon. David Petraeus, the CIA director, concurred with that view at the same hearing. Other senior United States officials, including Defence Secretary Leon Panetta and General Martin Dempsey, the chairman of the Joint Chiefs of Staff, have made similar statements in recent television appearances. “They are certainly moving on that path, but we don’t believe they have actually made the decision to go ahead with a nuclear weapon,” Clapper told the Senate Select Committee on Intelligence.

Critics of the American assessment in Israel and some European capitals point out that Iran has made great strides in the most difficult step toward building a nuclear weapon, enriching uranium, the NYT dispatch said. That has also been the conclusion of a series of reports by the International Atomic Energy Agency’s inspectors, who on Friday presented new evidence that the Iranians have begun enriching uranium in an underground facility.

Once Iran takes further steps to actually enrich weapons grade fuel - a feat that the United States does not believe Iran has yet accomplished - the critics believe that it would be relatively easy for Iran to engineer a warhead and then have a bomb in short order, the NYT said. They also criticise the CIA for being overly cautious in its assessments of Iran, suggesting that it is perhaps overcompensating for its faulty intelligence assessments in 2002 about Iraq’s purported weapons programmes, which turned out not to exist. In addition, Israeli officials have challenged the very premise of the 2007 intelligence assessment, saying they do not believe that Iran ever fully halted its work on a weapons programme. Yet some intelligence officials and outside analysts believe there is another possible explanation for Iran’s enrichment activity, besides a headlong race to build a bomb as quickly as possible, according to the NYT.

They say that Iran could be seeking to enhance its influence in the region by creating what some analysts call strategic ambiguity.

 Rather than building a bomb now, Iran may want to increase its power by sowing doubt among other nations about its nuclear ambitions. Some point to the examples of Pakistan and India, both of which had clandestine nuclear weapons programme for decades before they actually decided to build bombs and test their weapons in 1998.

“I think the Iranians want the capability, but not a stockpile,” said Kenneth Brill, a former US ambassador to the International Atomic Energy Agency who also served as director of the intelligence community’s National Counterproliferation Center from 2005 until 2009.

A former intelligence official added: “The Indians were a screwdriver turn away from having a bomb for many years. The Iranians are not that close.”

David Kay, who was head of the CIA’s team that searched for Iraq’s weapons programmes after the United States invasion, was cautious about the quality of the intelligence underlying the current American assessment.

“They don’t have evidence that Iran has made a decision to build a bomb, and that reflects a real gap in the intelligence,” Kay was quoted as saying. “It’s true the evidence hasn’t changed very much” since 2007, he added. “But that reflects a lack of access and a lack of intelligence as much as anything.”