(Reuters) - A loud noise was heard on the White House's South Lawn just before U.S. President Barack Obama and his family were due to take off by helicopter, a White House pool report said on Saturday.

It said the noise prompted Secret Service agents to move the press back into the briefing room and lock the doors. Obama and his family were not yet on the South Lawn.

No further details were immediately available.

(Reporting by Washington Speed Unit; Editing by Catherine Evans)