Russian propagandists targeted the popular news-sharing website Reddit to influence American political debate, a US website has claimed.

It had been widely presumed that Reddit, a hub for campaigning, activism and often extreme views, would be a logical target for any manipulation.

It has yet to publish its own investigation into Russian activity.

Now news site the Daily Beast says it has obtained files showing a Russian troll farm was active on Reddit.

The Daily Beast says it has obtained leaked documents from within Russia's Internet Research Agency (IRA), the country's most prominent troll-factory.

The US government has already charged 13 Russians, linked to the agency, with attempting to manipulate American voters using social media.

The Russian organisation is alleged to have had a budget of more than a million dollars, which the US claims was used to buy advertising on sites such as Twitter and Facebook.

So far, Reddit has not been included in the US Senate's investigation into Russian meddling in the 2016 presidential election.

But some reports have suggested that could soon change.

Influence

The documents discovered by the Daily Beast are said to detail the Internet Research Agency's efforts on Reddit.

The site says the agency employed "online agitators" to help posts from its own propaganda websites rise to the top of Reddit.

It says the organisation used proxy servers to mask the location of its work.

Also targeted were the Yahoo-owned blogging platform Tumblr, and the viral joke site 9gag.

Senate investigations have singled out Russian efforts on other platforms

The Daily Beast said the documents - which the BBC has not seen - included the names of US-based activists who the Russians were trying to contact.

The publication said its reporters contacted several of these people and confirmed online conversations had taken place.

As has been a pattern with Russian efforts discovered to date, there is no outright support of any particular candidate or viewpoint.

Instead it seems Russia's aim was to provoke and divide Americans on the internet and, as a result, in the physical world too.

'Not provided evidence'

The Daily Beast said it had given Reddit the opportunity to comment on the story, but that repeated requests were ignored.

Reddit replied on Friday, telling the BBC: "Reddit was not provided evidence of accounts or other data that would enable us to identify misuse or manipulation of the platform by users."

Reddit has gained a reputation as being something of a haven for some of the more extreme views that have been pushed off other platforms like YouTube and Twitter.

The site consists of many user-generated sections, known as subreddits, that focus on a particular topic or place, such as r/football or r/SanFrancisco.

Submissions are up- or down-voted by other users, with the most popular rising to the top of each respective section.

Steve Huffman has said he would what remove a controversial pro-Trump section

Posts that are wildly popular make their way to the front page and thus an audience of several million around the world every day.

One particular subreddit, r/The_Donald, is arguably the most powerful and coordinated pro-Donald Trump community on the internet, endorsed by the President himself who, while campaigning, used the forum to answer questions posted by users.

Reddit has taken several steps to limit r/The_Donald's impact, including blocking popular submissions from appearing on Reddit's front page.

In a move he later apologised for, Reddit co-founder and chief executive Steve Huffman admitted personally editing comments posted on r/The_Donald.

Trump supporters on the site accuse Reddit of censorship and bias, but other users accuse Reddit of doing too little, pointing to many instances in which posts on r/The_Donald have gone against Reddit's policies.

Mr Huffman acknowledged that some users on r/The_Donald did break the site's rules, but said the volunteer moderators on the section were proactive in removing such material.

'Disturbing'

Aside from information involving Reddit, the Daily Beast said the leaked documents included "at least 21" accounts on Tumblr, the blogging site acquired by Yahoo in 2013.

Oath, the Verizon company that now owns Yahoo, said the findings were "deeply disturbing".

"We’re committed to creating platforms consumers can trust, and any abuse of our services is deeply concerning to us," it said.

Like Reddit, Oath has not been called upon to provide evidence to the various committees looking into the issue of Russian influence online.

Facebook, Twitter and YouTube-owner Google have all appeared in front of US politicians on several occasions to explain their investigations and subsequent efforts to prevent similar activity from Russia - or other countries - in the future.

Yet unlike its competitors, which have workforces in the tens of thousands, Reddit is a comparatively tiny company.

As of July last year, the company had just 230 employees, yet it is ranked the sixth most popular website on the internet by traffic monitoring service Alexa.

It has a so-called "anti evil" team to combat abuse, described in job postings as "small and scrappy".