Hillary's election would mire US govt in crisis: Trump

"Hillary is likely to be under investigation for a very long time," Trump said during series of election rallies in Michigan.

He made the remarks in the context of the FBI reopening the investigations against Clinton's email scandal, less than 11 days before the presidential elections.

The 70-year-old business tycoon said one of Clinton's longtime supporters, a top Democratic Pollster, Doug Schoen, is now totally withdrawing his support.

He wrote an article entitled 'I'm a Democrat, I worked for Bill Clinton, but I can't vote for Hillary', Trump said.

"Schoen writes: 'I am now convinced that we will be facing the very real possibility of a constitutional crisis with many dimensions and deleterious consequences should Secretary Clinton win the election. Schoen warns that if Hillary is elected, she would be under protracted criminal investigation - and probably a trial of a sitting President," Trump said.

"The investigation will last for years, a trial will probably start, nothing will get done, and our country will continue to suffer," the Republican presidential nominee said.

"She is unfit and unqualified to be President, and her election would mire our government and our country in a constitutional crisis we cannot afford. We need to be going to work for the American people - we can't do that with Hillary in the White House trying to avoid prosecution," Trump warned.

He said Clinton's corruption is a 'threat to democracy' and asserted that the only way to save democracy was to get out and vote by the millions.

"The Clinton crime spree ends on November 8," he said.

Noting that the FBI has reopened its investigation into Hillary Clinton and has discovered another 650,000 emails, he alleged that the former secretary of state lied under oath when she said she turned over all of her work-related emails.

"Just one more lie out of so many. This is the biggest scandal since Watergate. Hillary wants to blame everyone else for her mounting legal troubles, but she has brought this all onto herself. Hillary is the one who set-up an illegal private email server in a closet to shield her criminal activity," he alleged.

"Hillary is the one who engaged in a corrupt Pay-For-Play scheme at the State Department - and now there are 5 FBI probes into the Clinton Foundation and their pay-for-play activities. Hillary is the one who sent and received classified information on an insecure server, putting the safety of the American people under threat," he said.