ILLINOIS (Reuters) - Presumptive Democratic Presidential nominee Hillary Clinton warned supporters on Wednesday (July 13) that her Republican rival Donald Trump poses a "threat" to US democracy.

During a wide-ranging speech on rising racial tensions delivered at the place where President Abraham Lincoln made a historic speech on slavery, Mrs Clinton portrayed Mr Trump as a dangerously divisive figure stoking tensions at a critical time.

His campaign, Mrs Clinton said, "is built on stoking mistrust and pitting American against American".

Her speech comes after weeks of rising tensions over police killings of African-Americans and the killing of five police officers in Dallas.

She said Mr Trump was intolerant of dissent and said he could use the government to silence his critics.

"Imagine if he had not just Twitter and cable news to go after his opponents, but also the IRS, or for that matter the entire military," Mrs Clinton said.

The real estate billionaire is turning the party that abolished slavery into the party that instills fear and division, she added.

"This man is the nominee of the party of Lincoln. We are watching it become the party of Trump. And that's not just a huge loss for our democracy, it is a threat to it," she said.