Speaking to NBC's "Meet the Press" on Sunday, Paul Manafort, Trump's new convention manager, said the Texas senator's campaign is "threatening" people at conventions.
"You go to these county conventions, and you see the tactics, Gestapo tactics, the scorched-earth tactics," Manafort said. "We're going to be filing several protests because reality is, you know, they are not playing by the rules."
Manafort's comments come as Cruz captured 34 delegates in Colorado as the state chose to hold a GOP convention rather than a primary or caucus. CBS News reports Cruz has added delegates in South Carolina and Louisiana, despite Trump winning those states' primaries.
Trump tweeted that "the people of Colorado had their vote taken away from them by the phony politicians," calling it "totally unfair."
Trump also accused the Cruz campaign of offering "goodies."
"I win a state in votes and then get non-representative delegates because they are offered all sorts of goodies by Cruz campaign. Bad system!" Trump posted.
Cruz campaign spokeswoman Catherine Frazier lashed out at the Trump camp, saying they are following the rules.
"It's no surprise that Trump's team will lash out with falsehoods to distract from their failure, as they have the entire time," she told CBS News in a statement. "We have earned our success by working hard to build a superior organization and are working within the process and rules that have been established – which has led now to four consecutive wins, 12 wins total."
The Texas senator said there will be a fight at the Republican convention in Cleveland.
"It's going to be a battle in Cleveland to see who can earn a majority of the delegates," Cruz said.
According to CBS News, Trump has 743 delegates, compared to Cruz's 540. A Republican candidate needs 1,237 delegates to secure the nomination.
for more features.