Donald TrumpDonald John TrumpTrump's top adviser on Asia to serve as deputy national security adviser United Auto Workers strike against GM poised to head into eighth day Trump doubles down on call to investigate Biden after whistleblower complaint: 'That's the real story' MORE on Monday ripped Republican presidential rival Ted CruzRafael (Ted) Edward CruzTrump walks tightrope on gun control State Department's top arms control official leaving Sanders NASA plan is definitely Earth first MORE over controversial mailers from the Texas senator in Iowa that Trump said are "unbelievable" and "a total fraud." 

"I saw actually an actual copy and it looks right out of municipal government. And it says, you know, violation and it's absolutely amazing," Trump said on MSNBC's "Morning Joe."
"I've never seen anything like. It's a total fraud. Now I don't know if they're going to do ... he's being investigated over it, but it's a total fraud. It's a disgrace that they can do it," Trump said. 
Cruz's campaign distributed "report cards" to potential supporters, marked "voting violation," and purporting to show grades for the past votes of Iowans and their neighbors. 
Iowa's secretary of State rebuked Cruz over the weekend for the controversial mailer used to encourage voters to turn out for the caucus Monday night. 
Cruz defended the mailers Saturday night, describing them as "routine" and saying his campaign seeks to us "every tool we can" to encourage voting, according to The Associated Press.
"It's either a violation or it's not. If it was a violation, I think the secretary of State would have said so," Rep. Steve King (R-Iowa), Cruz's national co-chairman, said during an interview on CNN's "New Day."

Trump, who on Sunday called the mailers "dishonest and deceptive," is battling Cruz in the Hawkeye State where recent polls have shown him with an edge over the Texas senator. Sen. Rand Paul (R-Ky.) has joined Trump in the criticism of Cruz.