Facebook Inc <FB.O> said on Monday that it had changed some of the procedures for its "Trending Topics" section after a news report alleging it suppressed conservative news prompted a U.S. Congressional demand for more transparency.
The company said an internal probe showed no evidence of political bias in the selection of news stories for Trending Topics, a feature that is separate from the main "news feed" where most Facebook users get their news.
But the world's largest social network said in a blogpost that it was introducing several changes, including elimination of a top-ten list of approved websites, more training and clearer guidelines to help human editors avoid ideological or political bias, and more robust review procedures.
Earlier this month, a former Facebook contractor had accused the company's editors of deliberately suppressing conservative news. The allegations were reported by technology news website Gizmodo, which did not identify the ex-contractor.
The report led Republican Sen. John Thune to write a letter demanding that the company explain how it selects news articles for its Trending Topics list.