The U.K.'s data protection watchdog ordered Facebook's auditors to back down from a probe into a political analytics company accused of wrongly harvesting the data of millions of its users.

The tech giant was planning to investigate Cambridge Analytica's servers and systems, but the Information Commissioner's Office told Facebook on Monday that it should withdraw from the research firm's London premises. The ICO said it would seek to gain its own warrant to access the company's computers and servers.

Facebook had said Monday that it was pursuing a forensic audit of Cambridge Analytica and had hired digital forensics firm Stroz Friedberg to determine whether the data analytics company still possessed Facebook user data.

But in an updated statement later that day, Facebook said: "Independent forensic auditors from Stroz Friedberg were on site at Cambridge Analytica's London office this evening. At the request of the U.K. Information Commissioner's Office, which has announced it is pursuing a warrant to conduct its own on-site investigation, the Stroz Friedberg auditors stood down."

Reports over the weekend said political analytics firm Cambridge Analytica was able to collect data on millions of people's profiles without their consent. The firm worked on Facebook ads with President Donald Trump's campaign in 2016, but the data allegedly held by Cambridge Analytica was not used in the 2016 Trump presidential election campaign, the company claims.

According to Christopher Wylie, a whistleblower who worked for Cambridge Analytica during the election, the company mined the data of 50 million Facebook profiles.

Cambridge academic Aleksandr Kogan and his company Global Science Research created an app called "thisisyourdigitallife," which used psychological tests to gather data on users. According to Wylie, Kogan then passed that data onto Cambridge Analytica, enabling the latter to develop software that could potentially influence voters.