SYRACUSE, N.Y. — In his ever-escalating fight with the Republican National Committee, Donald Trump warned Saturday that party leaders should reform its system for selecting a nominee or face a "rough July" when it holds its convention in Cleveland.

"The Republican National Committee, they’d better get going, because I’ll tell you what: You’re going to have a rough July at that convention," Trump said Saturday afternoon at a campaign rally in Syracuse. "You’d better get going, and you’d better straighten out the system because the people want their vote. The people want their vote, and they want to be represented properly."

Trump has won many more states than his Republican rivals, but it's becoming increasingly unlikely that he will collect enough support from the state delegates who ultimately pick the Republican nominee at the party's July convention. Trump currently has 744 delegates, and Sen. Ted Cruz (R-Tex.) has 545. There are 852 delegates remaining. To lock up the nomination, Trump would need support from a total of 1,237 delegates. Meanwhile, Cruz has been snapping up the support of delegates at state conventions, thanks to his campaign's deeper understanding of state-by-state nominating rules and a stronger ground game.

Following a big win in Florida last month, Trump's top campaign staffers acted as if they had mostly locked up the nomination — only to be seemingly caught off guard by the new fight for delegates. Trump has quickly hired a number of seasoned operatives with experience in delegate wooing and convention maneuvering, but he has also chastised the party for having such a complicated system for picking the nominee and accused party leaders of rigging the system to work against him, a charge they strongly deny.

Trump's comments came just days before members of the Republican National Committee are set to hold their spring meeting in Hollywood, Fla. While there are no current plans to discuss revamping rules for the national convention, the nomination process or how delegates are chosen, some RNC members have openly floated ideas for changing how a nominee would be selected.

Regardless, any decisions made at the spring meeting have no bearing on the convention. A separate convention rules committee is the only vehicle to make changes for how the convention will be conducted. The body, made up of convention delegates, is scheduled to meet in Cleveland on the Friday before the convention formally begins to consider any proposed rules changes. It's at that forum that Trump and his supporters could petition to make any changes.

Last month, Trump said that if Republican leaders ignore the votes of millions of party members and enter a brokered convention, "I think you'd have riots, I think you'd have riots."

Roger Stone, one of Trump's close advisers who has no formal role with the campaign, said earlier this month that he might leak the hotel room numbers of delegates who were expected to support Trump but switch loyalty. 

On Saturday, Trump seemed to make a new appeal to party leaders, suggesting that he should not be penalized for rejecting the support of super PACs and largely self-funding much of his campaign. Trump said had he arranged for his own super PAC, it would have collected 10 times more money than one that supported former Florida governor Jeb Bush, exceeding $100 million.

Trump said that he decided not to spend his more limited funds to send teams of staffers to Colorado, which appointed delegates at a convention instead of through a caucus or primary.

"Look, I used to be the ultimate establishment person, nine months ago," Trump said. "I was like the perfect person. I gave massive campaign contributions to everybody. … But I saw the system, and the system is not working. And the system is all rigged, as far as the delegate stuff is going. Now look, I guess I’m complaining because it’s not fair to the people."

Trump wondered aloud whether it was unwise for him to reject help from "phony PACs," and he repeatedly seemed to suggest that the Republican Party — which he has been colorfully bashing for months — should give him a break.

"What I like is spending the least and having the best result, because that’s what we want to do with our country: spend the least and have the best result," Trump said. "So the system is rigged. It’s a bad system, it’s a dirty system, and we’re going to do something about it. And maybe that’ll take place the next time around, meaning in four years, because the system is a bad, bad system, and they’ve got to do something about it."

Trump said that it was out of character for him to reject money of any sort but that it was the right thing to do in this election.

"This is like counter to my life — my whole life I’ve been taking money, I make money, I make money. I took a million dollar loan in a relatively short period of time, I built a company that’s worth more than 10 billion dollars," Trump said, as the crowd loudly cheered, a jarring change from when Mitt Romney ran for president in 2012 and tried to play down his wealth.

The first half of Trump's more than 50-minute speech in Syracuse was much more structured than the speeches he gave at rallies just weeks ago, suggesting a maturation in his campaign strategy. He hyper-focused on economic issues, promising to bring back jobs from overseas and improve New York's economy. But toward the end of the speech, as the roaring crowd egged him on, Trump seemed to settle back into his own campaign style, riffing on the authenticity of his New York accent, reflecting on the threat of heroin in beautiful New Hampshire and slamming the Ricketts family, major GOP donors who have funded efforts to defeat him.

The New York Republican primary is Tuesday, and there are 95 delegates at stake that are awarded on the basis of election results in each congressional district, along with some that are at-large. Each of the state's 27 congressional districts has three delegates. If a Republican candidate wins more than 50 percent of votes in a district, he gets all three delegates. There are also 11 at-large delegates who will be selected at a state committee meeting on May 18. The final three delegates are the state party chairman and two RNC committee members, who can vote for whomever they want.

Trump has dominated polls of New York Republican voters, and he is expected to win a large number of delegates on Tuesday.

"It’s a movement like they’ve never seen before," Trump said of support for his candidacy. "It’s a movement that maybe isn’t ever going to happen again, and the only way you stop the movement is if we don’t do a good job on Tuesday. That’s what it is. We have to keep it going."

Ed O'Keefe contributed to this report.