The Republican National Committee (RNC) has succeeded in its dogged effort to get current leading GOP 2016 presidential candidate Donald Trump to sign off on a pledge stipulating that he will endorse the party's nominee and forego all plans of a third-party run.

"I will be totally pledging my allegiance to the Republican Party and the conservative principles for which it stands," Trump announced at a New York City press conference on Thursday. "And we will go out and we will fight hard and we will win."

According to NBC, the often outspoken real estate mogul later added that the RNC has been "absolutely terrific" and "fair" to him since he became a presidential candidate.

"I see no circumstances under which I would tear up that pledge," he said.

In yet another statement released later in the day, Trump added that such a unified approach offers the best way for Republicans to take over the White House after President Barack Obama's second term has ended.

"I am leading in all local and national polls --- my whole life has been about winning and this is what must be done in order to win the election and, most importantly, to Make America Great Again!" he added.

Trump spent part of the day early Thursday meeting and hammering out specific details with Republican National Committee chairman Reince Priebus. The RNC had privately reached out to other Republican candidates in recent days to gauge their support for such a pledge.

Several national polls indicate a third-party run by Trump could result in double-digit support for him, greatly reducing any legitimate chance Republicans might have of securing the votes needed for a return to the Oval Office.

During last month's first Republican debate, Trump was the only candidate participating who refused to rule out a potential third-party run if he did not win the Republican nomination.

CNN reports campaign lawyers contacted by the network stress that the pledge is not a legally binding document.