SAN FRANCISCO, March 22 (Reuters) - Facebook Inc Chief Executive Mark Zuckerberg apologized on Wednesday for mistakes his company made in how it handled data belonging to 50 million of its users and promised tougher steps to restrict developers' access to such information. The world's largest social media network is facing growing government scrutiny in Europe and the United States about a whistleblower's allegations that London-based political consultancy Cambridge Analytica improperly accessed user information to build profiles on American voters that were later used to help elect U.S. President Donald Trump in 2016. "This was a major breach of trust. I'm really sorry this happened. We have a basic responsibility to protect people's data," Zuckerberg said in an interview with CNN, breaking a public silence since the scandal erupted at the weekend. Zuckerberg said in a post on Facebook the company "made mistakes, there's more to do, and we need to step up and do it." He said the social network planned to conduct an investigation of thousands of apps that have used Facebook's platform, restrict developer access to data, and give members a tool that lets them to disable access to their Facebook data more easily. His plans did not represent a big reduction of advertisers' ability to use Facebook data, which is the company's lifeblood. Zuckerberg said he was open to additional government regulation and happy to testify before the U.S. Congress if he was the right person. "I'm not sure we shouldn't be regulated," he told CNN. "I actually think the question is more what is the right regulation rather than yes or no, should it be regulated? ... People should know who is buying the ads that they see on Facebook." Zuckerberg said Facebook was committed to stopping interference in the U.S. midterm election in November and elections in India and Brazil.
