Presidential candidate Donald Trump isn't afraid to insult people but on Thursday he found a new group to add to his hit-list: Republican Jewish voters.

The billionaire businessman was speaking at a Republican Jewish Coalition event in Washington DC along with other GOP presidential hopefuls.

While the other candidates used their platform to attack US President Barack Obama, Trump turned on his audience during his remarks.

"You're not going to support me because I don't want your money," he told them.

That prompted Ari Fleischer, White House press secretary under George W Bush, to respond "What the hell does that mean?" on Twitter.

That wasn't all from Trump. "Is there anybody that doesn't re-negotiate deals in this room?" he asked. "Perhaps more than any room I've ever spoken to."

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Undivided capital

One prominent Jewish organisation defended Trump's remarks but encouraged him to clarify what he meant.

"We do not believe he intended his comments regarding negotiations and money to relate specifically to their Jewishness, but we understand that they could be interpreted that way," said Jonathan A Greenblatt, chief executive of the Anti-Defamation League.

Trump also drew boos from the audience when he refused to categorically state that Jerusalem should be the undivided capital of Israel. "Who's the wise guy?" Trump asked in response, pointing to an audience member who was booing.

Trump said he wants to reserve judgement on the Jerusalem question until after he meets with Israeli Prime Minister Benjamin Netanyahu. Although Trump said that he would be travelling to Israel, details have not been officially worked out, a campaign spokesman told Al Jazeera.

When asked which Arab leaders he would be willing to work with, Trump struggled to name one. "The King of Jordan seems like a nice man," he said.

In spite of his remarks, Trump did give the audience some red meat after calling Obama "the worst thing that's ever happened to Israel".