STATEN ISLAND, N.Y. — Republican presidential candidate Donald Trump said Sunday that he hopes a contested Republican convention in July "doesn't involve violence" if he is denied the nomination during second-ballot voting.

"I hope it doesn't involve violence. I hope it doesn’t. I'm not suggesting that," Trump told reporters on Sunday here in Staten Island. “I hope it doesn’t involve violence, and I don’t think it will. But I will say this, it’s a rigged system, it’s a crooked system. It’s 100 percent corrupt.”

Trump said Saturday that the Republican National Committee is in for a "rough July" if he does not receive the nomination despite his overwhelming delegate lead. If the billionaire fails to cross the 1,237-delegate threshold necessary to clinch the nomination outright, anti-Trump conservatives hope to challenge him at the convention and install an establishment-friendly alternative.

This summer's political conventions could get heated – but it certainly wouldn't be the first time. (Peter Stevenson/The Washington Post)

Trump came to the outer New York City borough on Sunday to speak at the Richmond County Republican Party Lincoln Day Lunch. The New York Veteran Police Association presented Trump with an award before the brunch.

Trump's campaign has stumbled in recent weeks as the battle for the nomination has become more intensely focused on courting delegates in the case of a contested convention. Non-traditional contests like those in Colorado and Wyoming have exposed strategic weaknesses the campaign has scrambled to rectify.

The process of courting delegates, Trump said, is "rigged" because "you're basically buying people." He said he is not interested in "playing the rules game."

"Nobody has better toys than I do. I can put them on the best planes and bring them to the best resorts anywhere in the world," Trump said. “You’re basically saying, ‘Delegate, listen, we’re going to send you to Mar-a-Lago on a Boeing 757, you’re going to use the spa, you’re going to do this, you’re going to do that, we want your vote. That’s a corrupt system."

“That has nothing to do with democracy," he added.

He added that he believes the system will ultimately change before the 2020 presidential election because of his complaints against the RNC, though he conceded that it will not have an effect this year.

The billionaire remained bullish Sunday that he will win the nomination outright, saying that "when I get the nomination, we're going to come together" and beat Democratic front-runner Hillary Clinton.

"You know the story. It's crooked Hillary. She's as crooked as they come," Trump said at the brunch. "We are going to beat her so badly."