Donald Trump believes that Hillary Clinton's campaign chairman John Podesta doesn't come off well in a trove of stolen e-mails published by WikiLeaks.

"This guy Podesta is a nasty guy," Trump said, at a rally in Naples, Fla. "I wouldn't want people speaking like that about me behind my back."

Trump referenced a new e-mail published by WikiLeaks today surrounding the San Bernardino terror attacks.

"What he is saying about her, he's gotta be fired," Trump said.

A new e-mail released Sunday by WikiLeaks discusses Clinton's tenure as secretary of state, specifically that Clinton could face questions about whether she did enough to tighten visa restrictions and could have prevented the shooters from entering the country. Tashfeen Malik, one of the two shooters responsible for the attack, received a visa to enter the U.S. in 2014.

"It is just a matter of time before the Republicans (certainly) and the media (likely) begin to try to use San Bernandino as a sign that things were broken while she was Sec State and that she did not do enough to fix them," political operative Ron Klain said in an e-mail to campaign staff. "And I don't know if saying, 'Hey, this really wasn't a problem until after I left State' is going to cut it."

However, Podesta was only copied on that e-mail exchange and did not weigh in.