White House sources say “situation contained, no threat”

The situation is under control and there is no threat, said White House sources without elaborating Saturday after a security alert and lockdown. They were triggered by an unexplained blast on the White House’s South Lawn which sent forth a plume of dark smoke, 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 on put on hold for Secret Service agents to investigate the incident.