US Republican presidential candidate Donald Trump says that his Democratic rival Hillary Clinton should be imprisoned for her use of a private email server while she was US secretary of state.
"I will say this, Hillary Clinton has got to go to jail," Trump told supporters Thursday at a rally in San Jose, California, as he slammed Clinton's foreign policy speech earlier in the day in which Clinton called Trump dangerous and "temperamentally unfit" to be president.
"Folks, honestly, she is guilty as hell," Trump said. "Hillary Clinton has to go to jail."
Trump's criticism of Clinton was among his strongest in a growing escalation of words between the two presidential candidates ahead of California's June 7 state primary election.
Earlier Thursday, Clinton unleashed a blistering criticism of Trump on foreign policy and said he was "unfit" to be president.
More than 2,000 emails sent and received by Clinton while working as the top US diplomat between 2009 and 2013 include classified information, which the government bans from being handled outside secure, government-controlled channels.
In a report issued last week, the US State Department’s inspector general said Clinton’s use of a private email server at her home in New York violated the department’s record-keeping rules and that it would have been rejected had she asked department officials.
Clinton also faces a separate probe by the Federal Bureau of Investigation (FBI).
Republican lawmakers in Congress appear ready to protest strongly if the FBI closes its investigation without delivering indictments or offering a public explanation.
And although Clinton leads Democratic presidential candidate Bernie Sanders in the delegate count, Sanders argues that he still has a path to the Democratic presidential nomination.
During her speech on Thursday, Clinton said "Donald Trump's ideas aren't just different -- they are dangerously incoherent."
"They're not even really ideas -- just a series of bizarre rants, personal feuds, and outright lies."
"He's not just unprepared -- he's temperamentally unfit to hold an office that requires knowledge, stability and immense responsibility," she continued.
The speech was intended to undercut Trump's ability to woo national security-focused independent and Republican voters, the aide said.
"This is not someone who should ever have the nuclear codes," she declared, claiming Trump could start a war just because somebody "got under his very thin skin."