LONDON, March 22 (Xinhua) -- Facebook and Cambridge Analytica remain at the center of an international outcry over the way data of over 50 million Facebook members was used without their knowledge.

British Prime Minister Theresa May has raised the issue in the British parliament, saying the two companies involved in the data scandal should fully comply with investigations. The country's Information Commissioner's Office is investigating the allegations.

May said: "I would expect Facebook, Cambridge Analytica and all organizations involved to comply fully with the investigation that is taking place."

A House of Commons committee also said it wanted Facebook founder Mark Zuckerberg to appear before it to give evidence about the use of personal data by Cambridge Analytica.

Following protests about the data breach, Zuckerberg broke his silence, apologizing to Facebook users in a statement, admitting that Facebook "made mistakes" and a "breach of trust" had occurred.

"We have a responsibility to protect your data, and if we can't then we don't deserve to serve you," Zuckerberg said in the statement.

He also said: "While this specific issue involving Cambridge Analytica should no longer happen with new apps today, that doesn't change what happened in the past."

Zuckerberg pledged that a series of measures would be taken to address current and past problems.

The outcry erupted after a whistleblower revealed to the Observer newspaper how Cambridge Analytica used personal information taken without authorization in early 2014 to build a system that could profile individual U.S. voters, in order to target them with personalized political advertisements.

Cambridge Analytica has denied any wrongdoing, but the company has suspended its chief executive officer Alexander Nix.

As well as the claims that the harvested data could have been used by the company to influence the election which saw Donald Trump win the race to the White House in 2016, there are suspicions it could also have been used to influence the British referendum which led to people voting to leave the European Union (EU).

An academic is also allegedly involved in this scandal. Facebook found out that Cambridge Analytica had acquired the data in 2015 from a company called Global Science Research, which was run by Aleksander Kogan, a psychology lecturer at the University of Cambridge.

Members of the Psychometrics Center at the University of Cambridge, which has worked for years on tools that can analyze anonymous Facebook data for political and psychological insights, raised questions about Kogan's alleged use of university research to develop a similar app for Cambridge Analytica that could be used commercially, according to the Financial Times, quoting messages seen by the newspaper.

The Psychometrics Center has clarified in a statement that it had never worked with, or in any way collaborated with, SCL Elections Ltd or any of its subsidiaries, including Cambridge Analytica.

"We have had no involvement of any kind with the Cruz or Trump campaigns, Leave.EU, or any other political campaigns of any kind anywhere in the world. Furthermore, no political organizations have ever been given permission to view, commercialize or otherwise use any data collected by the myPersonality project, which ran on Facebook between 2007 and 2012," the center said.

When personal data is collected for academic research, "it is important that data owners are aware of their data being collected for certain purposes and provide consent for such usages. We believe nobody should have a prediction made about them without their knowledge," Dr. Luning Sun, research director of the center, told Xinhua in an interview.

"I think that using Facebook or similar platforms should not mean that as a consequence you give up all privacy rights," Sun said.