(Reuters) - Cyber attackers have targeted Iranian infrastructure and communications companies, disrupting the Internet across the country, a state official was quoted as saying on Wednesday.
Iran, the world's No. 5 oil exporter, has tightened cyber security since its uranium enrichment centrifuges were hit in 2010 by the Stuxnet computer worm, which Tehran believes was planted by arch-adversaries Israel or the United States.
"Yesterday we had a heavy attack against the country's infrastructure and communications companies which has forced us to limit the Internet," Mehdi Akhavan Behabadi, secretary of the High Council of Cyberspace, told the Iranian Labour News Agency.
"Presently we have constant cyber attacks in the country. Yesterday an attack with a traffic of several gigabytes hit the Internet infrastructure, which caused an unwanted slowness in the country's Internet," he said.
"All of these attacks have been organized. And they have in mind the country's nuclear, oil, and information networks."
Israeli officials have threatened military action against the Islamic Republic's nuclear energy sites if Western sanctions on Tehran's banking and oil sectors do not persuade it to shelve its disputed atomic program.
Western powers suspect Iran is trying to develop the means to produce nuclear weapons. Tehran says it is enriching uranium only for civilian energy.
Last month a commander in Iran's elite Revolutionary Guards said it was prepared to defend itself in case of a "cyber war" and deemed it more dangerous than a physical confrontation.
Iranian authorities said in April that a computer virus was detected inside the control systems of Kharg Island - which handles the vast majority of Iran's crude oil exports - but the terminal remained operational.