Republican presidential candidate Donald Trump said on Thursday that Jewish-American voters would be partly to blame if he loses the Nov 5 election to Vice President Kamala Harris, the Democratic candidate.

During comments to the Israeli-American Council National Summit in Washington, the former president lamented that he was trailing Harris among American Jews.

Israel would likely cease to exist within two years should Harris win the election, and Jews would be partly to blame for that outcome because they tend to vote for Democrats, Trump argued.

"If I don't win this election - and the Jewish people would really have a lot to do with that if that happens because if 40%, I mean, 60% of the people are voting for the enemy - Israel, in my opinion, will cease to exist within two years," Trump told the crowd.

Trump was citing a poll that he said showed Harris polling at 60% among American Jews. He also lamented winning less than 30% of the vote among American Jews in the 2016 election, which he won, and the 2020 election, which he lost to Democratic President Joe Biden.

It was not clear what poll the former president was citing, but a recent Pew Research Survey found American Jews favour Harris over Trump by a margin of 65% to 34%.

Trump made similar comments at a separate summit earlier in the evening, also in Washington, which was dedicated to fighting antisemitism in America.

The Trump campaign has made winning over Jewish voters in key battleground states a priority. U.S. Jews have leaned heavily towards Democrats in federal elections for decades and continue to do so, but just a small shift in the Jewish vote could determine the winner in November.

In the crucial battleground of Pennsylvania, for example, there are over 400,000 Jewish people, in a state Biden won by 81,000 votes in 2020.

"Preemptively blaming American Jews for your potential election loss does zero to help American Jews," said Jonathan Greenblatt, national director of the Anti-Defamation League.

Morgan Finkelstein, a spokesperson for the Harris campaign, criticized Trump for at times associating with anti-Semites. Trump has rejected all accusations of anti-Semitism, noting during his speeches on Thursday that he has a Jewish son-in-law.

"When Donald Trump loses this election, it will be because Americans from all faiths, ethnicities, and backgrounds came together to turn the page on the divisiveness he demonstrates every day," Finkelstein said in a statement to Reuters.

During his comments, Trump did not address a CNN report published earlier in the day regarding the Republican gubernatorial candidate in North Carolina, Mark Robinson.

That report alleged Robinson once called himself a "black NAZI!" in comments posted on a pornography website and that he advocated for the return of slavery.