The Guardian believes there is an "orchestrated" pro-Kremlin campaign in the comments on its website.
Readers' editor Chris Elliott has highlighted a number of suspcious comments which have emerged on stories about the Ukraine conflict in recent months.
Former Russia correspondent Luke Harding, who is now based in Ukraine after being expelled from Russia in 2011, has been labelled a "Russian hater" and appears to have been targeted.
Harding described the alleged campaign as a "well-attested phenomenon" with Elliott highlighting an article on The Guardian from 2012 that reported:
A pro-Kremlin group runs a network of internet trolls, seeks to buy flattering coverage of Vladimir Putin (pictured: Reuters) and hatches plans to discredit opposition activists and media, according to private emails allegedly hacked by a group calling itself the Russian arm of Anonymous.
"The group has uploaded hundreds of emails it says are to, from and between Vasily Yakemenko, the first leader of the youth group Nashi [and] now head of the Kremlin's Federal Youth Agency, its spokeswoman, Kristina Potupchik, and other activists. The emails detail payments to journalists and bloggers, the group alleges."
Elliott reports a senior moderator as saying: “We can look at the suspicious tone of certain users, combined with the date they signed up, the time they post and the subjects they post on. Zealous pro-separatist comments in broken English claiming to be from western countries are very common, and there's a list of tropes we've learnt to look out for. These posts may be suspicious but it's when the content of them breaks our community standards that we will step in.
"A larger problem on these threads is users accusing each other of being 'bots', 'trolls' or 'astroturfers', usually wrongly. These accusations do break the community standards (they're essentially abusive statements) and moderators take a hand here. We will also, obviously, act against abusive statements at the expense of our writers, of which Luke receives a substantial number. Those are more likely to be the reason for us taking action on these threads. It's only when an account crosses those lines that we step in."
Elliott wrote: “In fairness there is no conclusive evidence about who is behind the trolling, although Guardian moderators, who deal with 40,000 comments a day, believe there is an orchestrated campaign. Harding, who is inured to the abuse, would simply like better systems to deal with it, as would the moderation and community teams.”
Elliott highlighted the alleged pro-Putin campaign after receiving complaints from readers over the comments.
One complaint read: "One need only pick a Ukraine article at random, pick any point in the comments at random, and they will find themselves in a sea of incredibly aggressive and hostile users (the most obvious have accounts created since February 2014 … but there also exist those who registered with the Guardian before the high point of the crisis) who post the most biased, inciteful [sic] pro-Kremlin, anti-western propaganda that seems as if it's taken from a template, so repetitive are the statements. Furthermore, these comments are consistently capturing inordinate numbers of 'recommends', sometimes on the order of 10 to 12 times what pro-Ukrainian comments receive."