Trump quickly backtracks on Clinton's emails: 'I think I read that and I heard it'
Donald Trump speaks to NBC News anchor Lester Holt on June 23, 2016. (Media Matters)

Donald Trump was unable to produce any evidence on Thursday when pressed over his claims regarding Hillary Clinton's email server, Media Matters reported.

"She shouldn't have had a personal server, okay?" Trump told NBC News anchor Lester Holt. "She shouldn't have had it, it's illegal. What she did is illegal. Now she might not be judged that way because we have a rigged system, but what she did is illegal. She shouldn't have had a personal server."

"But is there any evidence it was hacked other than routine phishing?" Holt asked.

"I think I read that, and I heard it," Trump replied. "And somebody also gave me that information."

"Where?" Holt asked.

"I will report back to you," Trump said. "I will give it to you."

"You said it with such certainty yesterday," Holt observed, making reference to the presumptive GOP presidential nominee's speech attacking Clinton on Wednesday.

"I don't know if certainty. Probably she was hacked," Trump said. "You know what, you can be hacked and not know but it she probably was hacked. The fact is she should not have had a personal server."

Trump also dodged when Holt pressed him on his accusation that Clinton was "sleeping" during the fatal attack in Benghazi, which Clinton refuted while speaking under oath.

"She might have been sleeping. What?" Trump said. "Because she put out a tweet, somebody said she put out a tweet, therefore she wasn't sleeping? Nobody else could put out a tweet?"

Watch footage from the interview, as posted by Media Matters, below.