Soon after he entered office in 2009, US President Barack Obama secretly began ordering sophisticated cyber-attacks on computer systems that run Iran’s main nuclear enrichment facilities, The New York Times reported on Friday.The Times report was based on interviews with former American, European and Israeli officials involved in the program and other experts.Reuters and Yaakov Katz contributed to this report.The US and Israel developed the Stuxnet worm that attacked Iran’s nuclear program in 2010, according to the sources.Experts have in the past estimated that the virus set back the Islamic Republic’s nuclear program by 18 months to two years. However, according to the Times, some experts are skeptical; they say that Iran’s uranium enrichment program has recovered and the country now has enough fuel for five or more weapons.On Monday, security experts discovered a new data-stealing virus dubbed Flame, and found that the largest number of infected machines are in Iran, followed by Israel and the Palestinian territories, then Sudan and Syria.Experts say the virus has lurked inside thousands of computers across the Middle East for as long as five years as part of a sophisticated cyberwarfare campaign.It is the most complex piece of malicious software discovered to date, said Kaspersky Lab security senior researcher Roel Schouwenberg, whose company discovered the virus. The results of the Lab’s work were made available on Monday.If the Lab’s analysis is correct, Flame could be the third major cyber-weapon uncovered after the Stuxnet virus, and its data-stealing cousin Duqu, named after the Star Wars villain.A day after reports of Flame emerged, Strategic Affairs Minister Moshe Ya’alon fueled speculation of Israeli involvement in the cyber-attack when he told Army Radio that “whoever sees the Iranian threat as a serious threat would be likely to take different steps, including these, in order to hurt them.”Senior defense officials expressed confidence that Israel’s military networks were secure and protected from cyber-attacks.“Israel is blessed to be a nation possessing superior technology. These achievements of ours open up all kinds of possibilities for us,” Ya’alon said.Under president George W. Bush, the US began building a complex cyber-weapon to try to prevent Tehran from completing nuclear weapons work without resorting to risky military strikes against Iranian facilities, current and former US officials familiar with the program said.Obama accelerated the efforts after succeeding Bush in 2009, according to the sources, who spoke on condition of anonymity because of the classified nature of the effort. The weapon, called Stuxnet, was eventually used against Iran’s main uranium enrichment facilities.The effort was intended to bridge the time of uncertainty between US administrations after the 2008 presidential vote in which Obama was elected, and to allow more time for sanctions and diplomacy to prevent Iranian nuclear weapon development, according to the current and former officials.The sources provided rare insight into the US development of its cyber-warfare capabilities and the intent behind it.One source familiar with the Bush administration’s initial work on Stuxnet said it had delayed Tehran’s nuclear program by about five years.“It bought us time. First, it was to get across from one administration to the next without having the issue blow up. And then it was to give Obama a little more time to come up with alternatives, through the sanctions, et cetera,” the source said.Only in recent months have US officials become more open about the work of the United States and Israel on Stuxnet, the sophisticated cyberweapon directed against Iran’s Natanz nuclear enrichment facility that was first detected in 2010.The cyber-attacks provided the United States with an avenue to try to stop the Islamic Republic from producing a weapon without turning to military strikes against Iranian facilities – all at a time when US forces were fighting wars in Iraq and Afghanistan, the sources said.In the end, senior US officials agreed that the benefit of stalling Iran’s nuclear program was greater than the risks of the virus being harnessed by other countries or terrorist groups to attack American facilities, one source said.Two sources with direct knowledge of the US program said it cost hundreds of millions of dollars to carry out.The United States for years has been developing – and using – offensive cyber-capabilities to interfere with the computers of adversaries, including during the Battle of Falluja in Iraq in 2004 and in finding Osama bin Laden and other al-Qaida figures, the sources said.Last year, the United States also explicitly stated for the first time that it reserved the right to retaliate with military force against a cyberattack.The Times reported on Friday that from his first months in office, Obama secretly ordered attacks of growing sophistication on the computer systems running the main Iranian nuclear enrichment facilities, greatly widening the first sustained US use of cyber-weapons. The Times said the attacks were codenamed Olympic Games.White House spokesman Josh Earnest declined comment on the substance of the Times article, but denied “in the strongest possible terms” that it was an authorized leak of classified information. Obama is seeking reelection on November 6 in part on the strength of his foreign policy achievements.Reuters reported last Tuesday that the United Nations agency charged with helping member states secure their national infrastructures plans to issue a sharp warning about the risk of the Flame computer virus.Iranian officials have described the cyber-attacks as part of a “terrorist” campaign backed by Israel and the United States.Some current and former US officials, who asked not to be named, criticized the Obama administration for talking too freely to the media about classified operations.Rep. Peter King (R-New York), the chairman of the House of Representatives Committee on Homeland Security, said, “I believe that no one, including the White House, should be discussing cyber-attacks.”“The US will now be blamed for any sophisticated, malicious software, even if it was the Chinese or just criminals,” said Jason Healey, who has worked on cyber-security for the US Air Force, White House and Goldman Sachs, and is now with the Atlantic Council research group.