Facebook has agreed to refund some advertisers who had spent over $1,000 to promote ads in violation of its news feed policy banning fake news. The refund process is ongoing, according to a company spokesman.

Since the year started, news outlets and brands have accused Facebook of promoting fake news. If a search page includes any false articles, it will lower the item’s visibility on news feeds. The company recently added a public Feedback section to the “Your News Feed” page, asking users to take a look at problematic articles and issue feedback. The company says it is also taking steps to improve its processing of reports of fake news.

Huffington Post published a guide to reporting on the spread of fake news in December. Many media outlets’ warnings against spreading fake news rely on Facebook, along with Twitter and Google, as the main platforms used by users.

The circulation of fake news can be particularly harmful to news brands, which are at least partly based on their journalistic integrity. For example, the article by mistake circulated last year that the BBC was predicting a stock market crash, included headlines such as “BBC Stock Market Crash Forecast: Come and Take It,” with some of the articles in the story having been proven false.

The company says in its written response to The New York Times that it “acknowledges that many news outlets have been concerned about reports of false stories appearing in their headlines.” Facebook says it’s using a combination of three different human editors and artificial intelligence to help detect whether the fake news reported by users may be harmful to users, users or other sites.

The New York Times reported that the Facebook has so far refunded more than $500 to marketers who violated the policy by promoting fake news in their pages and ads.

The Times said it has received dozens of complaints from advertisers of ads in violation of the policy and plans to publish more stories in the coming days detailing the refund process and its effects.

Facebook will continue to guarantee news literacy tools to train users and encourage them to be critical of the posts in their feed. The company says its tools include a filter that prevents users from connecting with fake news sites.