CLEVELAND — Donald J. Trump told donors at a private meeting on Thursday that an endorsement from Senator Ted Cruz “doesn’t mean anything” to him and noted that his former opponent was run out of the convention hall on Wednesday night after being booed during his speech.

According to a Politico report, Mr. Trump also had some harsh words for Gov. John Kasich of Ohio, another former rival who has not endorsed him, saying, “If I got beaten as bad as Kasich got beaten by me, I wouldn’t support him either.”

The remarks came on the final day of the Republican National Convention and hours before Mr. Trump was due to accept the party’s nomination. The gathering has been marked by intraparty fighting, which came to a head on Wednesday night when Mr. Cruz was heckled and shunned during his address for not endorsing Mr. Trump despite signing a pledge last year to support the eventual nominee.

Mr. Trump mocked the pledge at the meeting, according to Politico, saying that he believed he could have defeated his Republican rivals if he ran as an independent, citing Reince Priebus, the chairman of the Republican National Committee.