Republican primary front-runner Donald TrumpDonald John TrumpAssange meets U.S. congressman, vows to prove Russia did not leak him documents A history lesson on the Confederacy for President Trump GOP senator: Trump hasn't 'changed much' since campaign MORE in an interview broadcast Sunday refused to escalate his feud with Sen. Ted Cruz (R-Texas).

When asked about his chief political rival during an interview with ABC News's Jon Karl, the businessman said Cruz, who has recently taken the lead in Iowa, was a “nice guy.”

“He is a very nice guy. He has been very respectful,” Trump said.

Trump also said when he entered the presidential race that he had no idea he would sustain such a dramatic lead over his competitors, ABC News reported.

“It’s a very, very big lead, so I didn’t think that we would have that,” he said.

The real estate mogul added that it will be easier to beat Democratic front-runner Hillary ClintonHillary Rodham ClintonAssange meets U.S. congressman, vows to prove Russia did not leak him documents High-ranking FBI official leaves Russia probe OPINION | Steve Bannon is Trump's indispensable man — don't sacrifice him to the critics MORE in a general election than to win the Republican nomination.

“I am winning. I am beating everybody and, in my opinion, beating Hillary is easier than beating these people,” he said of his Republican adversaries, according to ABC News.

Trump has been leading polls in the Republican primary race nationally for more than five months, although he was briefly overtaken by retired neurosurgeon Ben Carson in November, according to the RealClearPolitics Average of polls.

Cruz, however, currently holds a slim lead over Trump in the Iowa caucuses.