Gholam Reza Jalali, who heads an Iranian military unit in charge of fighting sabotage, told state radio that the oil industry was the only governmental body seriously affected and that all data lost were later retrieved.
"This virus penetrated some fields. One of them was the oil sector. Fortunately, we detected and controlled this single incident," Jalali said.
Obiso, whose agency is helping to direct the international response to Flame, said the virus first came to the group's attention in mid-April and researchers have been working on unraveling its code since.
"We still think Flame has much more to show," he said.
The Russian Internet security firm Kaspersky Lab ZAO said the Flame virus has struck Iran the hardest, but has been detected in the Palestinian territories, Sudan, Syria, Lebanon, Saudi Arabia and Egypt.
It also has been found in Israel — leading some Israeli security officials to suggest the virus could be traced to the U.S. or other Western nations.
Experts describe it as a multitasking mole. It can wipe data off hard drives, but also be a tireless eavesdropper by activating audio systems to listen in on Skype calls or office chatter. It also can also take screenshots, log keystrokes and — in one of its more novel functions— steal data from Bluetooth-enabled mobile phones.
Israeli's vice premier on Tuesday did little to deflect suspicion about the country's possible involvement.
"Whoever sees the Iranian threat as a significant threat is likely to take various steps, including these, to hobble it," Moshe Yaalon told Army Radio when asked about Flame. "Israel is blessed with high technology, and we boast tools that open all sorts of opportunities for us."
Iran says is has previously discovered one more espionage virus, Duqu, but that the malware did no harm Iran's nuclear or industrial sites. Jalali said Flame is the third.
Dozens of unexplained explosions also have hit the country's gas pipelines in the past two years. Officials have not linked them to cyberattacks, but authorities have not closed the books on the investigations.
Murphy reported from Dubai, United Arab Emirates. Associated Press writers Raphael Satter in London and Josef Federman in Jerusalem contributed to this report.
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