Donald Trump demanded the Justice Department appoint a special prosecutor to go after Hillary Clinton for actions related to her email scandal and "pay-to-play" State Department, the Republican nominee told attendees at an Akron, Ohio, rally Monday evening.

"The Justice Department is required to appoint an independent special prosecutor because it has proven itself to be, really, sadly, a political arm of the White House. Nobody has ever seen anything like this before," said Trump, who took the stage nearly an hour before he was scheduled to speak. "The amounts involved, the favors done and the significant number of times it was done require an expedited investigation by a special prosecutor immediately, immediately, immediately."

"Some former prosecutors have even suggested that the coordination between the pay-for-play State Department and the Clinton Foundation constitute a clear example of RICO (Racketeer Influenced Corrupt Organization) enterprise," Trump added.

The FBI will release up to 15,000 unpublished emails that were recovered by the FBI from Clinton's private server. The State Department is in the process of assessing which ones can be released to Judicial Watch.

The billionaire businessman said after the FBI's failure to recommend charges against Clinton that an independent probe is critical.

"If the Justice Department fails to do so, it will make it even clearer that a second of four primary constitutional Departments have been corrupted," he said.

Earlier Monday, former President Bill Clinton attempted to appeal to voters by saying he would resign from the the Clinton Foundation's board if his wife wins in November. The decree was a step up from last week's promise from the Clinton campaign that it would no longer accept foreign donations if she won the Oval Office.