New York (CNN Business) Facebook released the results of a year-long, independent investigation of the company's alleged anti-conservative bias on Tuesday. Although Facebook (FB) has made some progress in eliminating anti-conservative bias, the company still has work left to do, the investigators say.

The eight-page report , conducted by former Republican Senator Jon Kyl and others at the law firm Covington and Burling, LLP, outlines concerns about Facebook's policies and the ways in which Facebook has already addressed them. The audit came at Facebook's request last year, following repeated claims of anti-conservative bias , including from President Donald Trump.

The report concludes that Facebook's efforts to counter misinformation have silenced some conservative voices on the platform. For example, some of the website Facebook relies on for fact-checking or flagging misinformation are considered by conservatives to be left-leaning. And Facebook's ads policy may have inadvertently restricted some anti-abortion advocacy.

Included the report is a new policy, in which Facebook will allow ads with images of people with medical tubes, as long as people featured are not in visible pain or distress and there are no blood or bruises. This change will likely benefit those who post ads for pro-life organizations and children's advocacy groups.

Former Senator John Kyl

Kyl's report says Facebook's previous policy on what they called "sensational" advertisements meant that pro-life ads that "focused on survival stories of infants born before full-term" were rejected from the platform. The policy "has been applied unevenly in the past," Facebook's VP of global affairs and communications Nick Clegg acknowledged in the blog post published Tuesday about the audit.

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