White House says FBI, Homeland Security Dept looking into AT&T outage

White House national security spokesperson John Kirby told reporters on Thursday the FBI and the Department of Homeland Security were looking into an AT&T outage, and that the Federal Communications Commission was in touch with the company.

"But the bottom line is we don't have all the answers," he added on the cause of the outage.

AT&T said three-quarters of its network had been restored after a cellular phone outage on Thursday disrupted calls and text messages for thousands of U.S. users.