Hillary Clinton's campaign on Wednesday said Donald Trump's suggestion that Russia should hack the Democrat's email system was an unprecedented move that has become a national security issue.
"This has to be the first time that a major presidential candidate has actively encouraged a foreign power to conduct espionage against his political opponent," said senior policy aide Jake Sullivan.
Speaking at a news conference in Florida on Wednesday morning, Trump said, "It would be interesting to see, I will tell you this.
Russia, if you're listening, I hope you're able to find the 30,000 emails that are missing."
He added, "I think you will probably be rewarded mightily by our press."
The Clinton campaign has been forceful about linking Russia to the leak as expert analyses concluded the connection is likely.