The White House is under security lockdown after mysterious bang

A blast on the White House’s South Lawn and a plume of smoke triggered a security alert Saturday, just before President Barack Obama and family were preparing to take off by helicopter to travel to Selma in Alabama. They had not yet reached the South Lawn. Their departure was put on hold to investigate. Secret Service agents moved the press back into the briefing room and placed the presidential residence under lockdown until the cause of the explosion is found.