DONALD TRUMP has signed a pledge not to run as an independent candidate if he fails to win the Republican party's nomination for president in 2016.
His announcement was a relief for the Republican party, which would see its support splintered if Mr Trump ever launched an independent run for the White House.
The billionaire property mogul also agreed to support the eventual Republican nominee should it not be him.
In a televised debate last month Mr Trump caused uproar when he refused to make such a commitment, saying: "I will not make the pledge at this time."
He was the only one of the 10 candidates on the debate stage who declined to do so. Mr Trump defended his stance by saying that the party had not treated him fairly or shown him respect.
Following more than a month of behind-the-scenes negotiations, Reince Priebus, chairman of the Republican National Committee, met the politician at Trump Tower in New York.
Mr Trump then confirmed at a press conference that he had signed the pledge, and showed the piece of paper.
He said: "The chairman has just left. The RNC has treated me with great respect recently. I just wanted fairness from the Republican party.
"We are leading in every single poll and the best way for the Republicans to win is if I win the nomination and go directly against whoever the Democrats put up. For that reason I have signed the pledge.
"I am pledging my allegiance to the Republican party and the conservative principles for which it stands. We will go out and fight hard and we will win, and most importantly we will make our country great again."
Mr Trump said he had received "absolutely nothing" from the Republican party in return for signing.
He added: "I cannot foresee any consequences under which I would tear up that pledge."
The Republican party has urged all candidates, not just Mr Trump, to sign the pledge, meaning that they will be committed to supporting the tycoon if he wins the nomination.
Jeb Bush, the former Florida governor who is one of Mr Trump's main rivals, said he would support whoever is victorious. Mr Bush said: "We need to be unified, we need to win."
A recent poll showed Mr Trump with 31 per cent support for the nomination among Republicans and Mr Bush with 12 per cent. The two candidates have been engaged in a bitter war of words in recent days.
In a speech in Spanish, delivered in Miami, Mr Bush questioned his rival's conservative credentials.
Mr Trump responded by calling Mr Bush a "low energy" candidate and criticised him for speaking in Spanish on the campaign trail. He said: "I like Jeb. He's a nice man. But he should really set the example by speaking English while in the United States."
A Republican National Committee official said: "This gets the proverbial elephant out of the room and allows the focus to be on winning the White House."