The noise prompted Secret Service agents to move the press back into the briefing room, lock the doors and put the building on lockdown.
The President and his family were not yet on the South Lawn when the noise was heard. There is also a fire reported in the area.
No further details were immediately available.
Obama and his family were about to depart by helicopter to Andrews Air Force Base to board Air Force One and travel to Selma, Alabama, to commemorate the 50th anniversary of a civil rights march.
