US President Barack Obama and Democratic presidential candidate HillaryClinton wave to the crowd on the third day of the Democratic National Convention at the Wells Fargo Center on July 27, 2016 in Philadelphia, Pennsylvania. Mrs Clinton is facing off with Republican candidate Donald Trump in one of the hotly contested American election. AARON P. BERNSTEIN | GETTY IMAGES | AFP.
Mrs Clinton acknowledges the crowd at the end on the fourth day of the Democratic National Convention at the Wells Fargo Center, July 28, 2016 in Philadelphia, Pennsylvania. CHIP SOMODEVILLA | GETTY IMAGES | AFP.
Mrs Clinton speaks during a primary night event in Brooklyn, New York, on June 7, 2016. PHOTO | GETTY IMAGES/AFP.
Mrs Clinton stands on stage with husband and former US President Bill Clinton during her primary night event at the Duggal Greenhouse, Brooklyn Navy Yard, in New York, on June 7, 2016. AFP PHOTO
Mrs Clinton greets supporters on her way to the stage during a primary night rally at the Duggal Greenhouse in the Brooklyn Navy Yard in the Brooklyn borough of New York City June 7, 2016. PHOTO | GETTY IMAGES/AFP
Mrs Clinton arrives on stage for a rally at Long Beach City College on the final day of campaigning in California in Long Beach on June 6, 2016. AFP PHOTO
Mrs Clintontakes photographs with supporters after a campaign rally at Sacramento City College in Sacramento, California, on June 5, 2016. AFP PHOTO
Mrs Clinton walks on stage after winning the highly contested New York primary on April 19, 2016 in New York City. SPENCER PLATT | GETTY IMAGES | AFP.
Mrs Clinton speaks during a campaign rally at Hartnell College on May 25, 2016 in Salinas, California. JUSTIN SULLIVAN | GETTY IMAGES | AFP.
Mrs Clinton during a "get out to caucus" event at Washington High School on January 30, 2016 in Cedar Rapids, Iowa. JUSTIN SULLIVAN | GETTY IMAGES | AFP.
Former US President Bill Clinton and daughter Chelsea Clinton listen as Democratic presidential candidate Hillary Clinton speaks at her New York Primary Night party in New York ON April 19, 2016. AFP PHOTO
Mrs Clinton gestures during a rally at Wayne State University in Detroit, Michigan, on October 10, 2016. AFP PHOTO
Mrs Clinton addresses the National Association of Black Journalists and the National Association of Hispanic Journalists August 5, 2016 in Washington, DC. WIN MCNAMEE | GETTY IMAGES | AFP.
Mrs Clinton addresses a North Carolina Democratic Party Rally at Wake Technical Community College September 27, 2016 in Raleigh, North Carolina. BRENDAN SMIALOWSKI | AFP.
Mrs Clinton and Colorado Governor John Hickenlooper wave to supporters after her speech at Adams City High School in Commerce City, Colorado, on August 3, 2016. PHOTO | AFP
Ms Clinton poses with students and faculty after speaking at Rancho High School in Las Vegas, Nevada. ETHAN MILLER | GETTY IMAGES | AFP