Reddit users shared links from fake sites thought to stem from an Iranian disinformation campaign.

The links came from six sites exposed by security firm FireEye as hoaxes, rather than the genuine British and American news sites they appeared to be.

Reddit users shared the links hundreds of thousands of times across popular communities with millions of subscribers.

It isn't clear whether the accounts sharing the material were all suspect, but most remain active on Reddit as of Wednesday morning.

A Reddit spokeswoman told Business Insider the site was investigating.

Reddit users shared thousands of links to fake sites that have now been exposed as part of a misinformation campaign from Iran.

We first became aware that Reddit was populated with the fake site links after it was pointed out by systems administrator Josh Russell on Twitter.

Business Insider's own further analysis found that Reddit users shared links to articles from six websites flagged by cybersecurity firm FireEye as part of a sophisticated influence operation, likely originating in Iran.

FireEye said on Monday that it had found many social media accounts associated with the six sites across Twitter, Facebook, Google+, YouTube, and Instagram. Twitter and Facebook said they had removed hundreds of accounts relating to the Iranian campaign.

The six websites were Liberty Front Press, US Journal, Real Progressive Front, British Left, Critics Chronicle, and Instituto Manquehue, all of which purported to be legitimate news sources.

Reddit users shared links from all six websites flagged as part of an Iranian misinformation campaign. Here's a set of links from Liberty Front Press, one of the fake sources. Shona Ghosh/Business Insider

A search for each website domain on Reddit shows that users posted thousands of links to popular communities such as r/worldnews, which has 19 million subscribers, r/news with 16 million subscribers, and r/atheism which has more than 2 million subscribers.

In some cases, several of the links to fake sites were "upvoted" by thousands of users, making them more visible and widely read.

Links were also posted to popular communities known for pushing an agenda, such as the generally pro-Trump r/conspiracy, the left-leaning r/esist, and the anti-Trump r/MarchAgainstTrump.

Not everything posted was fake news — rather the stories were clearly designed to push an agenda. For example, a true story about a British Airways stewardess being captured on camera going on a racist rant was posted on the fake website RPFront, and then to the r/racism community. According to FireEye, most of the sites favoured political stances in that Iranian interest.

Here's what FireEye said:

"Broadly speaking, the intent behind this activity appears to be to promote Iranian political interests, including anti-Saudi, anti-Israeli, and pro-Palestinian themes, as well as the advocation for specific U.S. political stances favorable to Iran, such as support for the U.S.-Iran nuclear deal (JCPOA). While in the context of the U.S.-focused activity, this also includes significant anti-Trump messaging and the alignment of social media personas with an American liberal identity, it is important to note that the activity extends well beyond U.S. audiences and U.S. politics."

It isn't clear how many of the users posting links to fake sites might have been aware they were part of a disinformation campaign, and how many may have been fake accounts. One of the most prolific posters of fake site links, PeterJackson2050, remains active on the site at the time of writing.

A Reddit spokeswoman told Business Insider: "We are aware of recent reports of malicious actors on social platforms. We are investigating our own site and, as we have done previously, will be transparent with our findings."