The US White House went into lockdown after a white van crashed into perimeter barriers just moments before Malcolm Turnbull was due to leave the building.
The Australian prime minister has been in Washington this week and, with his wife Lucy, had been meeting with President Donald Trump and the American first lady Melania.
A woman was behind the wheel of the white minivan when it smashed into a security barrier at 17th Street, the US Secret Service said.
The vehicle didn’t breach the White House security perimeter and the driver was immediately apprehended by uniformed Secret Service personnel.
No one was injured in the near-security breach and the Secret Service has stressed that no shots were fired during the incident.
Mr Turnbull and US President Donald Trump spent most of Friday together, including attending a 40 minute press conference.
Mr Turnbull is staying at Blair House, located a short distance from the White House and the incident.
Australian and US reporters in the White House press briefing room were taken to a basement while Secret Service and other authorities investigated the incident.