Facebook CEO Mark Zuckerberg responded to accusations its company's "trending" topics list was suppressing conservative media, saying Thursday the company was conducting an investigation.
No evidence of alleged manipulation had been found, but "if we find anything against our principles, you have my commitment that we will take additional steps to address it," Zuckerberg wrote in a Facebook post.
Tech news outlet Gizmodo reported Monday that a former Facebook worker alleged that articles from politically conservative outlets - particularly when written about conservative subjects - were deliberately omitted from Facebook's sidebar of popular stories.
The social media giant has denied the allegations amid outrage over the claims.
(Also see: Why Bias Complaints About Facebook's Trending Is a Big Deal)
Facebook said the popularity of news stories was determined by an algorithm, then audited - never manipulated - by review team members to confirm that the topics were in fact trending news items.
However according to Gizmodo, which also spoke to other former employees, stories covered by conservative media that were trending enough to be picked up by Facebook's algorithm were only included if they were also covered by "mainstream sites" such as The New York Times, the BBC or CNN.
There was no evidence that management mandated or was aware of any political bias at work, Gizmodo reported, noting that one former worker "described the omissions as a function of his colleagues' judgements."
Gizmodo reported that workers were told to put stories deemed as important by management in the trending news feed even if they weren't generating much buzz.
The charges unleashed a fierce debate in the US media and on the social network itself, which has around 1.6 billion users around the globe.
In his post, Zuckerberg also announced plans to invite "leading conservatives and people from across the political spectrum" to talk with him about accusations of political bias at Facebook.