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Republican presidential candidate Donald Trump acknowledges the crowd of supporters during a campaign rally in Phoenix, Arizona, June 18, 2016. Ralph Freso/Getty Images

Donald Trump spoke out Saturday against some Republicans trying to thwart him, calling them "an insurgent group." The New York real estate mogul also threatened to stop fundraising if the Republicans don't rally around him.

Trump's comments come amid his bid to get support from those who did not back him during the primary season, but his efforts appear to be running flat with the GOP national convention just a month away. The presumptive Republican nominee referred to "an insurgent group" trying to deny him delegates at the party's July convention.

"Now you have a couple of guys that were badly defeated and they're trying to organize maybe like a little bit of a delegate revolt," he said. "I thought they already tried that."

As the July 18-21 convention in Cleveland approaches, the “Anybody but Trump” movement, which is leading an effort to stop Trump from becoming GOP presidential nominee, would try to change party rules. The move comes as opinion polls indicate that Trump’s popularity is waning.

“This literally is an ‘Anybody but Trump’ movement,” Kendal Unruh, a Republican delegate from Colorado who is leading the campaign, said. “Nobody has any idea who is going to step in and be the nominee, but we’re not worried about that. We’re just doing that job to make sure that he’s not the face of our party.”

In recent weeks, Trump has angered party members with remarks about the federal judge handling his Trump University lawsuits, renewed calls for banning Muslims from entering the United States and shifting stances on the nation’s gun laws.

"It would be helpful if the Republicans could help us a little bit," Trump said Saturday, while expressing his frustration over the continuous resistance from Republicans who have been concerned over his inflammatory rhetoric.

Trump also said that if Republicans don't come together, he would stop fundraising and go back to largely self-funding his campaign, the Associated Press reported.

"I'd love to do it," Trump said. "You know, life is like a two-way street."

Trump has made several efforts to secure support from the lesbian, gay, bisexual and transgender community this week by speaking out in the wake of last Sunday’s shooting at the Pulse nightclub in Orlando, Florida, that left 49 dead and dozens injured. During his comments about the shooting, Trump also took shots at President Barack Obama.

"If you think Orlando was the end of it with this weak attitude and this pathetic president we have, it wasn't, folks," he said, adding: "You are going to have problems the likes of which you've never seen unless Donald Trump becomes your president."