The government of Iran has said that it detected the presence of the Duqu computer virus in its computer systems and is working to counter it.
According to Reuters, the country's civil defence organisation said the computer systems at critical nuclear sites were being scanned to find the virus and eradicate it.
The government also said that it had developed software that would help it detect and remove the virus from the systems.
Duqu was first discovered by Budapest-based Laboratory of Cryptography and System Security, Crysys, which revealed that the virus used some of the source code that was found in Stuxnet, which was discovered last year. Stuxnet was designed to take out Iran's nuclear plants.
While Stuxnet was designed to destroy industrial control systems used in nuclear plants, Duqu was been designed to gather data to orchestrate future cyber attacks.
"We are in the initial phase of fighting the Duqu virus. The final report which says which organizations the virus has spread to and what its impacts are has not been completed yet," said a government spokesperson.
"All the organizations and centers that could be susceptible to being contaminated are being controlled," he said.