Donald Trump has continued to dominate the race for Republican US presidential nomination by causing further controversy in the first debate between the 10 leading aspirants.
The 10 candidates, selected by Fox News on the basis of recent national polls, provided a frank and bruising exchange of views during their first debate on the road in Cleveland, Ohio.
The two-hour forum on the television channel gave Americans their first chance to compare the form of the Republican contenders for next year's presidential election.
The real estate mogul refused to rule out running as an independent, drawing boos from the audience at the opening debate today.
Another contender, Rand Paul, hit back at Mr Trump, saying he was hedging his bets because as a developer he was used to buying and selling politicians of all party allegiances.
But Republican National Committee chairman Reince Priebus said he was not particularly worried that Mr Trump would end up running as an independent.
Mr Trump continues to ride high in the polls, despite being slammed for discrediting 2008 Republican nominee John McCain's Vietnam prisoner of war experience.
The New York billionaire also stood by offensive comments he had made in the past about women, saying he did not have time for "total political correctness".
Mr Trump's visibility, plus his highly publicised entry into the Republican race, has created a positive feedback loop of political success; his name recognition spurs media coverage, which boosts his poll numbers and leads to more media coverage.
He is also popular because of his business credentials and has said he will be the "best jobs president that God ever created".
Anti-immigration rhetoric has been a central part of his campaign. He made headlines with his inaugural campaign speech in New York - accusing Mexico of "bringing drugs, and bringing crime, and their rapists" to the US.
He's also the spokesperson for ordinary Americans who feel disenfranchised - according to a CNN poll, just 16 percent of Republicans feel like they are represented in Washington.
"There's a silent majority out there," Mr Trump said in South Carolina last week. "We're tired of being pushed around, kicked around, and acting and being led by stupid people."
When the debate ended, commentators immediately praised the performances of Florida Senator Marco Rubio and Ohio Governor John Kasich.
But former Florida Governor Jeb Bush and Wisconsin Governor Scott Walker failed to provide their supporters with any stand-out moments.
Meanwhile, the Democratic Party has announced they will hold their first debate in Nevada in October, hosted by CNN.