Members of a Ted Cruz super PAC are offering $1.5 million to charities for veterans if Republican front-runner Donald Trump agrees to debate their candidate one-on-one before next week's Iowa caucus.

"Not only would this be a heck of a debate, but it would also be a terrific opportunity to generate millions of dollars for the veterans," donors from the pro-Cruz group, "Keep the Promise," said in a joint statement Wednesday night, NBC reported.

Trump recently announced he would not take part in the next Fox News debate, scheduled for Thursday night, because of an ongoing dispute with the network and his opposition to anchor Megyn Kelly serving as one of the event's moderators.

In his offer, announced during a West Des Moines rally, Cruz laid out his plans for how the two GOP leaders could make his offer come to fruition. He told a crowd he had reserved a venue in nearby Sioux City that seats up to 800 for Saturday night. He said half of the seats would be available to Trump to do with them as he pleased.

"We have the venue," he said. "We have the time. All we're missing is the candidate."

Indeed, Trump plans to be in Iowa Saturday night, where he has a rally planned for the Davenport area.

Earlier on Wednesday, Trump responded to Cruz's offer on Twitter:

As for his running feud with Kelly, Cruz chided Trump by asserting, "I promise you Putin is a lot scarier than Megyn Kelly. I'd like to hear Donald explain to the American people and to the people of Iowa how he is prepared to be commander-in-chief if he's terrified by a television host."

In a Monmouth University poll released on Wednesday, CNN reports Trump now leads Cruz in Iowa 30 percent to 23 percent.