Donald Trump. REUTERS/Darren Hauck Billionaire businessman Donald Trump said Wednesday that he would have a humane "deportation force" to kick out people who reside in the US illegally.

During a lengthy interview on MSNBC's "Morning Joe," host Mika Brzezinski repeatedly pressed the Republican presidential candidate on his sweeping plan to crack down on illegal immigration.

"OK, conceptually, I understand what you're saying and what you're describing. But still tell me the how. Are you going to have a massive deportation force?" Brzezinski asked, according to a show transcript.

Trump said he would have such a force but argued that it would not be as ominous as it might sound. Trump wants to deport everyone currently living in the US illegally, a number the Pew Research Center estimated to be above 11 million last year, but let the "wonderful cases" back into the country.

"You're going to have a deportation force, and you're going to do it humanely and you're going to bring the country — and, frankly, the people, because you have some excellent, wonderful people, some fantastic people that have been here for a long period of time," the real-estate mogul replied.

"Don't forget, Mika, that you have millions of people that are waiting in line to come into this country and they're waiting to come in legally," he continued. "And I always say the wall. We're going to build the wall. It's going to be a real deal. It's going to be a real wall."

Trump added that he spoke with New York Times columnist Thomas Friedman about the wall issue and stressed that legal immigration would be encouraged in his administration.

"But your friend Thomas Friedman called me and said, 'There should be a big door,'" he said. "I said, 'Going to be a big door.' I love the expression. There's going to be a big, beautiful, nice door. People are going to come in and they're going to come in legally. But we have no choice. Otherwise, we don't have a country."

Brzezinski did not seem entirely convinced.

"How are you going to pay for this?" she asked Trump.

"Very inexpensively," the candidate said. "If they came from a certain country, they're going to be brought back to that country. That's the way it's supposed to be. Now they can come back, but they have to come back legally."