Donald Trump's new convention manager accused Sen. Ted Cruz's campaign of using "Gestapo tactics" after the senator's organization swept Colorado's delegates on Saturday, shutting out the real estate mogul and further increasing the chances of a contested nominating convention in Cleveland.

"Well, he's threatening, you go to these county conventions, and you see the tactics, Gestapo tactics, the scorched-earth tactics," Paul Manafort said of Cruz in a Sunday interview on NBC's "Meet the Press."

The Gestapo was the secret state police of Nazi Germany, the regime's main tool of oppression in Europe.

Manafort, who helped manage the 1976 Republican convention for former President Gerald Ford, added that the Trump campaign would be filing "several protests" because Cruz's campaign wasn't "playing by the rules."

"Well, there's the law, and then there's ethics, and then there's getting votes. I'm not going to get into what tactics are used," Manafort said. "I happen to think the best way we're going to get delegates is to have Donald Trump be exposed to delegates, let the delegates hear what he says. He's done very well so far in putting himself in position by virtue of communicating."

In fact, it is Trump's circle that has been suggesting uncouth tactics. Longtime Trump ally Roger Stone, friend and former lobbying partner of Manafort, last week threatened to make public the hotel room numbers of delegates who switch from Trump to another candidate.

Trump's campaign appeared to have been out-organized by Cruz's team at several state GOP conventions -- where crucial delegates are elected. In Louisiana, Colorado, South Carolina and Iowa, Cruz's superior grass-roots team has racked up favorable delegates whose support he will need should the convention vote require multiple ballots.

A spokeswoman for Cruz did not immediately return a request for comment.

Editor's note: Donald Trump regularly incites political violence and is a serial liar, rampant xenophobe, racist, misogynist and birther who has repeatedly pledged to ban all Muslims -- 1.6 billion members of an entire religion -- from entering the U.S.