LONDON (AP) — Officers from Britain's information regulator are raiding the London offices of data firm Cambridge Analytica after being granted a warrant as part of an investigation into alleged misuse of personal information.

A High Court judge granted the warrant Friday evening. Soon afterward, 18 people, some in Information Commissioner's Office jackets, entered the company's central London offices.

The information commissioner is investigating whether the firm improperly used data from some 50 million Facebook users to target voters with ads and political messages.

Cambridge Analytica, best known for working on President Donald Trump's 2016 campaign, is at the center of an international storm over privacy and political manipulation.

Authorities in the United States and Britain are investigating whether it and Facebook broke the law in their use of personal information.