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Donald Trump told The O'Reilly Factor tonight that he doesn't like making personal attacks against Hillary Clinton, but the former secretary of state has left him no choice but to respond in kind.

Bill O'Reilly brought up a video posted on Trump's Instagram page that highlighted rape allegations against former President Bill Clinton.

"I'm not sure this is a good thing to do," O'Reilly said.

"I'm only responding to what they do," Trump said. "They've been nasty. She's been very nasty, and I said I'd like it to be on policy, Bill. I'd like it to be a straight, right down the middle..."

O'Reilly said he was worried that Trump's persistent attacks on the Clintons could make the country look bad.

"I don't like doing that, but I have no choice," Trump said. "When she hits me on things, I just have no choice. So you have to do it. It's unfair, and you know they're dirty players. They've been dirty players historically. And I have to fight back the way I have to fight back."

Trump said he would "much rather" make the campaign about "policy and issues."

O'Reilly also questioned Trump on the strategy against ISIS, transgender bathrooms and more.

Watch the full interview above.

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