Story highlights Trump says he will beat Hillary Clinton

Cites CNN poll showing GOP interest in his run

Washington (CNN) Donald Trump says Hillary Clinton's use of a personal email address on a private server crossed lines that former General David Petraeus never did.

"The fact is that what she has done is criminal," Trump told CNN's Jake Tapper on Sunday in a phone interview on "State of the Union."

Trump compared Clinton, the Democratic front-runner, to Petraeus, the former top U.S. military official in Iraq and Afghanistan and Central Intelligence Agency director who resigned amid allegations he allowed his mistress access to classified information.

"What she did is far worse than what General Petraeus did and he's gone down in disgrace," Trump said. "What he did is not as bad as what Hillary Clinton did, and it's similar. But it's not as bad. I mean, she got rid of her server, he never did anything like that."

The former general pleaded guilty to a misdemeanor charge of mishandling classified information.

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