U.S. President Barack Obama reportedly expanded cyberattacks on Iran's nuclear program even after the Stuxnet virus was accidentally made public in 2010.
"The New York Times" reported on June 1 that the operation, codenamed "Olympic Games," had begun under President George W. Bush.
The operation, aimed at preventing Tehran from developing nuclear weapons, caused widespread confusion at Iran's Natanz nuclear plant.
The newspaper reported that senior administration officials considered suspending it after the Stuxnet virus -- developed jointly with Israel -- escaped computers at Natanz and appeared in systems in several countries.
Obama eventually ordered the attacks to continue, and a week later, a newer version of Stuxnet temporarily brought down 1,000 of Iran's 5,000 nuclear centrifuges.
The "Times" article comes days after anti-virus experts discovered "Flame," a virus several times more sophisticated than Stuxnet.