Republican presidential front-runner Donald Trump on Thursday slammed his Democratic counterpart, Hillary Clinton, before a friendly audience in Washington D.C. - but not too friendly, as he himself reminded them.

The real estate tycoon, speaking to the Republican Jewish Coalition at the Ronald Reagan Building and International Trade Center, repeatedly reminded listeners that he is leading all national polls on the primary race, and assured them that he can will win the presidency over Clinton next November.

But he said she may be indicted first - and he told the crowd that he doesn't expect their support because he's not asking for any campaign donations.

Scroll down for videos

Republican Donald Trump addressed the Republican Jewish Coalition in downtown Washington DC on Thursday - but told them he does not expect to receive their support

The New York billionaire has been leading in the polls since late July

'I am in first place by a lot - it's not even close,' Trump said. 'Every single poll, every single state.. And I beat Hillary in a Fox poll, which is most important.'

Trump went on to say his office wall is 'loaded up' with awards from Jewish groups that he has received over the years, but added, 'the Christians are catching up.'

After calling President Barack Obama 'the worst thing that's ever happened to Israel,' he took on Obama's would-be successor, Clinton.

The former secretary of state is under investigation by the Justice Department for the potential mishandling of classified information that was routed through a secret email server based at her New York home while she was the nation's top diplomat from 2009 to 2013.

But Trump predicted that Attorney General Loretta Lynch won't indict Clinton for any wrongdoing.

'What she did was criminal, with the emails,' Trump said. 'She shouldn't be allowed to run. His attorney general is going to listen to him - look, I think it's very dishonest what's going on with our government... She can't go against him. Because if he says - boom, she gets indicted, and that's the end of it. That's the end of it.'

Hillary Clinton, the front-running Democratic presidential candidate, is guilty of 'criminal' acts for her use of a private email server, Trump said Thursday

Trump attacked Clinton for her private, home-based email server while she was secretary of state from 2009 to 2013

'So when you see Hillary backing up everything he says - I mean, he's got control of her. He's got total control. But I'll tell you, she shouldn't be allowed to run. What she did was a criminal act.'

Trump, a billionaire, also reminded his audience that because he is self-funding his campaign, he isn't asking for donations. In doing so, he called the Jewish lobby 'stupid.'

'I don't want your money, therefore you're probably not going to support me because stupidly, you want to give money. Trump doesn't want money. Even though he's better than all of these guys. Even though he's going to do more for Israel than anybody else,' Trump said.

And in case there was any lingering doubt, Trump told Thursday's crowd that he will definitely win the presidency next November.

'I'm going to win. I am. I'm going to win. I mean, unless something happens - you know, walk across the street and the wrong thing happens,' he said. 'But I believe I'm going to win. I really have just a great feeling about it. My life has been about winning. I've won.'

'So again, you're not going to support me even though you know I'm the best thing that could happen to Israel.. Isn't that crazy? But you want to control your own politician. That's fine. Don't worry about it, I understand.'