Donald Trump, brandishing a copy of his childhood Bible, again tried to undermine presidential rival Ted Cruz's claim to that key Iowa voting bloc.

"To the best of my knowledge, not too many evangelicals come out of Cuba," he told a Council Bluffs, Iowa crowd Tuesday. The line, an apparent reference to Cruz's heritage, began making appearances in Trump's stump speech when the Texas senator started claiming the top spot in some Iowa polls. "Just remember that, folks, when you're casting your ballot...." he added.

The Republican front-runner boasted of significant support from pastors and a strong poll showing among evangelicals, and called the Bible "superior" to his own book, "The Art of the Deal." He also took broader aim at elected officials like Cruz. "These politicians are all talk, no action. It's all bulls---," said Trump. "It's all bulls---, okay? It's all bulls---."

For more than an hour and a quarter, Trump largely stuck to his stump speech, including a defense of his admiration for Russian leader Vladimir Putin ("I like that Putin called me brilliant") and swipes at President Obama, Jeb Bush, U.S. trade negotiators, companies who engage in corporate inversion, gun-control advocates, protesters, reporters, and politicians who accept large campaign donations, among others. He included digs at former New York governor George Pataki, who suspended his campaign Tuesday night, and at Democratic front-runner Hillary Clinton. "If [the president has] got to be a woman, which I'm all in favor of some day, it shouldn't be Hillary," he said.

Speaking in western Iowa, Trump also took aim at those who argue that Iowa and New Hampshire should not always be the first states to cast presidential primary season votes. "It makes you important," he told the crowd, asking them to "think of it, if you were the 25th state, or the 50th state" to cast a vote.

Earlier in the day, Trump told reporters he would be spending "a minimum of $2 million a week, and perhaps substantially more than that" on his campaign, including major ad buys in early voting states like Iowa.

Almost as notable as what happened on stage in Iowa Tuesday was what didn't happen off it: in a break from the trend at recent events, Trump's speech remained free of surprise protester appearances or other notable interruptions.