Meanwhile, Trump is coming under fire over a tweet.

Trump retweeted a quote made famous by the Italian fascist dictator and Hitler's ally Benito Mussolini from a parody Twitter account.

It reads: "It is better to live one day as a lion than 100 years as a sheep."

Trump defended the retweet.

"It's ok to know its Mussolini, look Mussolini was Mussolini, it's a very good quote, it's a very interesting quote and I saw it, I know who said it but what difference does it make whether its Mussolini or somebody else? It's certainly a very interesting quote," Trump said in an appearance on NBC's Meet The Press.

"You want to be associated with a fascist?" asked host Chuck Todd.

"No I want to be associated with interesting quotes," Trump said.

Trump also tweeted his rejection of the recent endorsement of the former leader of the Ku Klux Klan, David Duke.