Facebook said in a statement that the goal of the 'news feed', which appears when users log in, 'is to show people the stories that are most relevant to them' and that its update 'helps you see more posts from your friends and family'.

The move comes after Facebook came under scrutiny from allegations by a former contractor that it was suppressing some political viewpoints in its 'trending topics'.

Facebook said its review found no bias, but that it would take steps to reassure users about the neutrality of the platform.

Facebook vice president Adam Mosseri said in a blog post that an updated algorithm that determines what users see would help people find information that matters to them.

"We are not in the business of picking which issues the world should read about," he wrote.

"We are in the business of connecting people and ideas – and matching people with the stories they find most meaningful.

"Our integrity depends on being inclusive of all perspectives and viewpoints, and using ranking to connect people with the stories and sources they find the most meaningful and engaging."

Even though Facebook has emphasized it does not want to be a media provider, surveys show it has become a key source of news for Americans and others, even if users visit the network for other reasons. A Pew Research Center survey last month found 66 percent of Facebook users get at least some news on the platform.

Global trends are similar. A survey across 26 countries by Oxford University's Reuters Institute for the Study of Journalism found 51 percent of respondents indicating they use social media for news, with 12 percent using it as their main news source.

Facebook was by far the most important source, used by 44 percent in the total survey.