WASHINGTON — Iran has already installed three-quarters of the nuclear centrifuges it needs to complete a deep-underground site for the production of nuclear fuel, international nuclear inspectors said Thursday. The finding will probably affirm the belief of Israeli officials that President Obama must make clear his intention to halt Iran’s program or give tacit approval for Israel to act on its own.
The report by the International Atomic Energy Agency, the last to be issued before the US presidential election, lays out in detail how Iran has used the summer to double the number of centrifuges installed under a mountain near the city of Qum. It also said that Iran has cleaned up another site where the agency has said it suspects that the nation conducted explosive experiments that could be ‘‘relevant’’ to the production of a nuclear weapon.
Based on satellite images, the IAEA said the cleanup has been so extensive that it would ‘‘significantly hamper’’ the ability of inspectors to understand what kind of work occurred there.
The report confirmed that a recent boast by Iran’s supreme leader, Ayatollah Ali Khamenei, that Iran had added nearly 1,000 centrifuges to the underground site was accurate. But it left open the question of what, exactly, Khamenei and other Iranian leaders intended to do with those, and whether, by racing ahead with construction, they sought negotiating advantage or to gain the capability to build a bomb before sanctions, sabotage, or military action could stop them.
On Thursday, Khamenei reiterated his stance that Iran was not seeking an atomic bomb. He criticized what he called the hypocrisy of the US-Israeli campaign against Iran. In a speech to the 120-member Nonaligned Movement meeting in Tehran, he also reminded the delegates that the United States is the only country that has ever used a nuclear weapon and that Israel has its own unacknowledged stockpile of nuclear weapons.
“A bitter irony of our era is that the US government, which possesses the largest and deadliest stockpiles of nuclear arms and other weapons of mass destruction and is the only country guilty of its use, is today eager to carry the banner of opposition to nuclear proliferation,’’ Khamenei said.
‘‘The US and its Western allies have armed the usurper Zionist regime with nuclear weapons and created a major threat for this sensitive region,’’ he continued. ‘‘Yet the same deceitful group does not tolerate the peaceful use of nuclear energy by independent countries, and even opposes, with all its strength, the production of nuclear fuel for radiopharmaceuticals and other peaceful and humane purposes.’’
With Obama administration officials warning Prime Minister Benjamin Netanyahu that a military strike on Iran’s nuclear sites would be counterproductive, the report has arguments for both sides in the debate.
The Israelis in favor of military action, led by Defense Minister Ehud Barak, an outspoken proponent of moving quickly against the Iranian program, will point to evidence that Iran has installed more than 2,100 of about 2,800 centrifuges destined for the underground site, called Fordow. More than 1,000 have been installed in the last three months.
For Barak, that is evidence that the ‘‘zone of immunity’’ he has warned about — the point at which Iran will be able to produce nuclear fuel from a site invulnerable to attack — will be reached in a matter of weeks.
But US officials urging caution will find plenty in the report to bolster their view. Only a third of the centrifuges at Fordow are operating, the inspectors reported, leaving open the question of whether Iran has run into technical difficulties or has made a political decision not to tempt its adversaries by rushing ahead in moving production of fuel to its best-protected facility.
And while the agency’s statistics show that Iran has, since February, doubled its stockpile of fuel enriched to 20 percent purity — a level that bomb experts say could be converted to bomb grade in a matter of months — it still does not possess enough of that fuel to produce a complete nuclear weapon. Most of its stockpile is composed of a lower-enriched fuel that would take considerably longer to make useful in a weapon.