(Reuters) - Social media website Reddit Inc, known for its commitment to free speech, will crack down on online harassment by banning or suspending users who target others, starting with those who have directed abuse at Chief Executive Steve Huffman.

Huffman said in an interview with Reuters that Reddit's content policy prohibits harassment, but that it had not been adequately enforced.

"Personal message harassment is the most cut and dry," he said. "Right now we are in an interesting position where my inbox is full of them, it's easy to start with me."

As well as combing through Huffman's inbox, Reddit will monitor user reports, add greater filtering capacity, and take a more proactive role in policing its platform rather than relying on community moderators.

Reddit said it had identified hundreds of the "most toxic users" and will warn, ban or suspend them. It also plans to increase staff on its "trust and safety" team.

Reddit's moves are the latest step by social media companies to adjust their policies in the wake of a polarizing U.S. election earlier this month in which their websites played a key role.

Facebook said it is reviewing its approach to so-called 'fake news' - generally sensational but fictitious reports designed to attract as many readers as possible - and banning some sites which host fake news from its advertising network. Twitter is also rolling out new tools to combat abuse.

On Reddit, a channel supporting the U.S. Republican party's presidential candidate Donald Trump, called r/The_Donald, featured racist and misogynistic comments, fake news and conspiracy theories about his Democratic challenger Hillary Clinton, along with more mainstream expressions of support for Trump.

Many of those supporting Trump were very active, voting up the r/The_Donald conversations so that they became prominent across Reddit, which is the 7th-most-visited U.S. internet site, according to web data firm Alexa.

Last week, Reddit banned Pizzagate, a community devoted to a conspiracy theory, with no evidence to back it up, that links Clinton to a paedophile ring at a Washington, D.C. pizza parlour, after it posted personal information in violation of Reddit policy.

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Huffman then used his administrative privileges to redirect abuse he was receiving on a thread on r/The_Donald to the community's moderators - making it look as if it was intended for them. Huffman said it was a prank, and that many Reddit users, including some Trump supporters, told him they thought it was funny, but it inflamed the situation.

Reddit has a more permissive attitude than Facebook and Twitter when it comes to what it allows on its site, but r/The_Donald users frequently crossed a line, Huffman said, including by trying to manipulate voting to ensure their posts appear on prominent Reddit pages.

Reddit has stepped up its efforts to combat abuse on the site over the past year, creating what it called an 'anti-evil" team of engineers dedicated to fighting harassment.

"The fact I was saying that combating harassment was important and then letting that openly happen to me, the CEO, there's a disconnect there," Huffman said.

In the past, Reddit has worked with moderators of communities to try to enforce its rules.

With r/The_Donald in particular, "we haven't found that to be particularly effective. We might see flashes of success, but things kind of revert," Huffman said.

Under its new strategy, Reddit will take a more active role in dealing with troublemakers, who Huffman said were an "infinitesimal" portion of Reddit's 250 million monthly visitors.

He stressed that the move was not political.

"We don't want to be censoring political beliefs, but then they do misbehave," he said. "That's why we have worked so closely with the r/The_Donald community. We tell them: don't force us to ban you."

The first wave of bans will likely be skewed to the r/The_Donald community because "that is a catalyst for a lot of this right now. That community is stirred up," Huffman said.

In a draft of a blog post to be published on Wednesday, Huffman said he had been asked by many Reddit users "to ban r/The_Donald outright, but he had rejected that idea, because "if there is anything about this election that we have learned, it is that there are communities that feel alienated and just want to be heard, and Reddit has always been a place where those voices can be heard."

(Reporting By Kristina Cooke; Editing by Jonathan Weber and Bill Rigby)