Security experts said on Monday a highly sophisticated computer virus is infecting computers in Iran and other Middle East countries and may have been deployed at least five years ago to engage in state-sponsored cyber espionage.

Evidence suggest that the virus, dubbed Flame, may have been built on behalf of the same nation or nations that commissioned the Stuxnet worm that attacked Iran’s nuclear program in 2010, according to Kaspersky Lab, the Russian cyber security software maker that took credit for discovering the infections.

Kaspersky researchers said they have yet to determine whether Flame had a specific mission like Stuxnet, and declined to say who they think built it.

Iran has accused the United States and Israel of deploying Stuxnet.Cyber security experts said the discovery publicly demonstrates what experts privy to classified information have long known: that nations have been using pieces of malicious computer code as weapons to promote their security interests for several years.

“This is one of many, many campaigns that happen all the time and never make it into the public domain,” said Alexander Klimburg, a cyber security expert at the Austrian Institute for International Affairs.

A cyber security agency in Iran said on its English website that Flame bore a “close relation” to Stuxnet, the notorious computer worm that attacked that country’s nuclear program in 2010 and is the first publicly known example of a cyber weapon.

Iran’s National Computer Emergency Response Team also said Flame might be linked to recent cyber attacks that officials in Tehran have said were responsible for massive data losses on some Iranian computer systems.

Kaspersky Lab said it discovered Flame after a U.N. telecommunications agency asked it to analyze data on malicious software across the Middle East in search of the data-wiping virus reported by Iran.