(CNN) -- Iran has been targeted by a new computer worm named Stars, according to an Iranian official.
"The damage is very slight in the initial stage," defense official Gholam Reza Jalali told the semi-official news agency Mehr.
It was unclear how long ago the worm was discovered or which systems in Iran it was designed to penetrate.
"It is compatible with the (targeted) system," Jalali said, and "it is likely to be mistaken for executable files of the government."
The announcement comes less than a year after Iranian nuclear facilities were targeted by a highly specialized computer worm called Stuxnet. It was apparently designed to secretly infiltrate the centrifuge machines that refine uranium and make them spin so fast they would break, according to David Albright of the Institute for Science and International Security.
"About 10% of the centrifuges were destroyed by Stuxnet," he said, which resulted in a setback for the Iranian nuclear program by as much as a year.
Iranian officials have said they believe last year's Stuxnet cyberattack originated in Israel and the United States, but officials from neither country have commented on the malware's origin. An American and an Israeli representative reached by CNN about the latest report again declined to comment.
An official with Symantec, a computer security firm that decoded the Stuxnet program last year, said a sample would be required for the company to forensically study the latest program for clues to its origin and its target.
"Until we have that, we can only guess at this point," said John Harrison, with Symantec's security response group.
An Iranian official at the United Nations, Alireza Miryousefi, said he could provide no further details on the latest attack. But in a statement, he said, "These sabotages -- (such) as producing computer viruses and the assassination of our nuclear scientists -- are outright criminal and illegal, aimed at preventing Iranians from implementing their peaceful nuclear rights."
Last year, in addition to the computer worm attack, two Iranian nuclear scientists were attacked by unknown assailants with car bombs. One of them was killed.
Albright warned that the latest cyberattack on Iran could prompt a response.
"Iran doesn't usually take things lying down," he said. "I'm sure they will start thinking about retaliation. They'll probably think of trying to launch a cyberattack."
CNN's Brian Todd and Pam Benson contributed to this report.