Iran's Ministry of Oil has cut off Internet access to six oil refineries following an apparent cyber attack targeting their networks, it was widely reported on Monday.

Representatives of the ministry said it has formed a "crisis committee," according to BBC Persian, citing Mehr News. The attacks are still ongoing.

Khark Island, which sits 16 miles off the northwestern coast of Iran, processes 90 percent of Iran’s crude exports. Iranian news websites have been scant on details, but apparently the "virus" targeted the Ministry of Oil, the National Oil Company, and a number of related companies.

The Fars News Agency, an Iranian news organization widely viewed as being pro-government, quoted Alireza Nikzad, a spokesperson for the Ministry of Oil, as saying that the attack did some limited damage but ultimately failed.

"This cyber attack has not damaged the main data of the oil ministry and the National Iranian Oil Company (NIOC) since the general servers are separate from the main servers. Even their cables are not linked to each other and are not linked to Internet service," Nikzad said.

The same official also claimed that the virus "burned" a few "motherboards and computers," adding that Iran’s energy sector has suffered the most cyberattacks over the last two years.

The report gave no indication of who was behind the malware attacks. In 2011, The New York Times reported that there was significant evidence to suggest that Israel and the United States were behind the Stuxnet worm, which disabled machinery at the Natanz nuclear facility in 2010.

The highly sophisticated Stuxnet exploited four previously unknown vulnerabilities in Windows and masterfully took advantage of weaknesses buried deep inside Siemens's Simatic WinCC Step7 software, which was used to control machinery inside Natanz. Stuxnet disrupted the Iranian nuke program by sabotaging the centrifuges used to enrich uranium. While the worm was designed to spread widely, it was programmed to execute its malicious payload against a highly selective list of targets.