"Just had a very nice meeting with @Reince Priebus and the @GOP. Looking forward to bringing the Party together --- and it will happen!" Trump tweeted
On Friday, a source familiar with the meeting told CNN it was arranged before Trump criticized the RNC at CNN's Town Hall on Tuesday. During the meeting -- CNN is told that Priebus told Trump that his disparaging comments about the RNC made things difficult with donors and activists and the party apparatus Trump will need if he is the GOP nominee.
The source added that Trump replied that he understood and would work to unify the party.
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The meeting was about convention rules, but mostly about delegates, another GOP source familiar with the meeting told CNN on Thursday. Another GOP source familiar with the meeting said much of the discussion was about how the delegate process works and laying that out for Trump and his team.
"The math and walking through the roadmap ahead," the source said.
Separately, RNC national spokeswoman Lindsay Walters described the meeting as "a productive conversation about the state of the race."
"The Chairman is in constant communication with all of the candidates and their campaigns about the primaries, general election, and the convention," Walters said in a statement. "Meeting and phone conversations with candidates and their campaigns are common and will increase as we get closer to November."
An RNC official told CNN that the Trump reached out to the RNC earlier in the week and said they were going to be in town "and wanted to stop by to say hello."
The Republican presidential front-runner has had a tumultuous relationship with party leaders throughout his campaign.
Delegates are also under a much more intense focus than past election cycles as the possibility of a contested convention increases.
Though Trump is far ahead in the delegate race, he could fall short of the majority mark needed to clinch the nomination outright. That would mean that after two ballots at the Republican National Convention, as many as eight in 10 of the nearly 2,500 men and women serving as delegates would be free to vote for whomever they choose.
The possibility of an open convention has riled Trump, who has repeatedly called out the RNC for treating him "unfairly." He has argued that he should get the nomination if he is the delegate leader going into the convention. But party rules require a majority of delegates to back a candidate, and there is doubt Trump will get the 1,237 he would need before the convention, which is held in July.
Trump further stirred the pot by saying at a Tuesday CNN GOP town hall that he would not uphold his earlier pledge to support the GOP nominee, no matter who it is.
That could put his delegate situation in further jeopardy. Time magazine reported
Thursday that South Carolina included the loyalty pledge as a requirement to be on the ballot, meaning that Trump's 50-delegate win there could be challenged.
But South Carolina GOP Chairman Matt Moore, who was quoted in the story saying there are unanswered questions, told CNN that is only conjecture.
"No one is seeking to unbind South Carolina's national delegates," Moore said. "I answered the process from a legal standpoint."
Campaign manager Corey Lewandowski confirmed to CNN Trump's earlier meeting at the hotel property included his national security team.
After meeting for at least two hours, the real estate mogul and his top aides were silent as they left the venue Thursday afternoon, declining to answer questions from CNN.
Trump has made more of an effort to build up his foreign policy credentials recently, including publicly naming his advisers on global affairs and national security.