WASHINGTON, Rajab 28, 1434, Jun 7, 2013, SPA -- Reports of sweeping U.S. government surveillance of Americans' phone and Internet activity put the Obama administration on the defensive on Friday, adding pressure on President Barack Obama to explain why such tactics are necessary, Reuters reported. The Washington Post reported late on Thursday that federal authorities have been tapping into the central servers of companies including Google, Apple and Facebook to gain access to emails, photos and other files allowing analysts to track a person's movements and contacts. That added to privacy concerns sparked by a report in Britain's Guardian newspaper that the National Security Agency (NSA) had been mining phone records from millions of customers of a subsidiary of Verizon Communications. Obama, who pledged to run the most transparent administration in U.S. history, did not mention the surveillance furor in two meetings with supporters on Thursday evening. He may be forced to breach the subject during his meetings with Chinese President Xi Jinping at a California summit on Friday, in which U.S. concerns about alleged Chinese hacking of American secrets were expected to be high on the agenda. -- SPA 18:36 LOCAL TIME 15:36 GMT www.spa.gov.sa/1118057