SAN FRANCISCO REUTERS March 21   
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. This follows allegations by a whistleblower that British political consultancy Cambridge Analytica improperly accessed users’ 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 told CNN, breaking a public silence since the scandal erupted at the weekend.   

 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 disable access to their Facebook data more easily.