A man who climbed over the White House fence near its western entrance gate and ran towards the presidential residence has been apprehended by uniformed Secret Service officers, US authorities said.
No-one was injured, said Max Milien, a spokesman for the Secret Service. The man's name was not released.
The man carried a rucksack as he clambered over the fence, then ran with his arms outstretched directly towards officers who ordered him to the ground with their weapons drawn.
The rucksack was later deemed to be safe, Mr Milien said.
The episode occurred as tourists and passers-by walked on Pennsylvania Avenue in front of the White House in Washington DC.
Officers immediately evacuated the avenue and Lafayette Square across from the White House.