Republican Presidential candidate Donald Trump addresses supporters during a political rally at the Phoenix Convention Center on July 11, 2015 in Phoenix, Arizona. Photo by Charlie Leight/Getty Images)

HOT SPRINGS, Ark. -- Donald Trump's controversial comments labeling illegal immigrants "rapists" who are bringing "drugs" and "crime" into the country have received widespread attention in recent weeks, and he has used them to argue in favor of dramatically intensifying efforts to secure the border and stem the flow of undocumented immigrants into the United States.

But what about the undocumented immigrants who are already living here? As president, what would Trump's plan be for them? It's not clear.

"We're going to do something with that," responded Trump when asked about it at a news conference here Friday evening. But what that something is, he wouldn't say. "The first thing we have to do is strengthen our borders," he added.

Later, he was asked whether he was planning to pursue mass deportations.

"I'm planning on building a tremendously powerful and strong border," replied Trump, sidestepping the question.

Trump came to Arkansas to speak at the state Republican Party's Reagan-Rockefeller fundraising dinner. In meandering remarks, he boasted of his qualifications for the presidency and slammed  Republican and Democratic opponents.