A man shot himself dead in front of the US Capitol on Saturday, sparking a temporary security lockdown at the complex on one of the busiest days for tourists in Washington.

The mother of a woman shot dead by police after a car chase that began when she tried to breach a barrier at the White House said her daughter suffered from post-natal depression.

A woman with a one-year-old child led the US Secret Service and police on a harrowing car chase through Washington DC, attempting to penetrate the security barriers at the White House and the Capitol before she was shot to death, police said. The child survived.

A woman driving a black Lexus tried to ram through a White House barricade then led police on a chase that ended in gunfire outside the Capitol.