United States lawmakers are calling for more regulation of Facebook. The move comes after reports that the social media company may have let a political organization have access to personal data from around 50 million Facebook users in 2014. Facebook wrote about the issue on Friday in a public online message, just before news media began reporting on the story. Reports said that Cambridge Analytica was given access to the data. The data company is linked to conservatives and is known for its work on Donald Trump’s 2016 presidential campaign. The reports also say the company may not have deleted, or removed, the data. Democratic U.S. Senator Amy Klobuchar wrote on Twitter that it is clear that companies like Facebook cannot “police themselves.” She added that Facebook chief Mark Zuckerberg should speak before the Senate Judiciary committee. Facebook announced late Friday it was banning Cambridge Analytica from its service for misusing data.