Trump: I was surprised Cruz dropped out, but hope he can get behind me

Republican presidential candidate Donald Trump
Luke Sharrett | Bloomberg | Getty Images

GOP likely presidential nominee Donald Trump told NBC on Wednesday he's confident he "can unite much" of the GOP. But after things said about his candidacy, the billionaire businessman said there are elements of the party he does not want under his tent.

Republican National Committee Chairman Reince Priebus on Tuesday night called Trump the "presumptive" nominee, after Sen. Ted Cruz dropped out of the race. Cruz threw in the towel after it became clear Trump would easily win the Indiana primary.

In a phone interview with NBC's "TODAY" show, Trump said Wednesday he spoke with Priebus and got assurances the party was behind him.

Trump also said he was surprised Cruz dropped out of the race. But in the Texas senator's case, he said, it would be nice if Cruz was eventually able to look past the tough campaign talk and support Trump's bid.

Trump's supporters 'locked in': Surrogate

In an interview on CNBC's "Squawk Box" Trump campaign spokeswoman Katrina Pierson addressed who's leading the Trump machine, as the real estate mogul surrounds himself with more seasoned advisors.

"Ultimately, Donald Trump is in charge of the Trump campaign and seeks advice from everyone around him," Pierson said.

In March, Trump brought in veteran political strategist Paul Manafort to manage the campaign's convention efforts. Since then, Manafort was put in charge of all activities related to the nomination process.

Manafort managed the 1976 Republican presidential convention for Gerald Ford and the 1980 convention for Ronald Reagan. He played leading roles in the 1988 and 1996 conventions of George H.W. Bush and Bob Dole, respectively.

As for the type of vice presidential running mate Trump might pick, Pierson said: "It's not just about who can win a state or who can bring this group. It's going to be about a team and an effort to get things done for the American people."

"This is something he's been thinking about for a very long some time," she said. "There's a lot of people that have been sent over to him to consider."