CLEVELAND - The Republican convention opened to chaotic scenes Monday as Donald Trump's opponents and supporters traded angry shouts, disrupting his plans for a smooth coronation as the party's White House nominee.
Jeers and yells filled the convention floor in Cleveland, Ohio as simmering divisions among thousands of Republican delegates spilled out into the open.
Anti-Trump Republicans - outraged that their party will be led by a man who described Mexicans as rapists and advocated banning Muslims - expressed fury when procedural machinations denied them a chance to register their discontent.
"We deserve to be heard, this is the people's convention!" said Diana Shores a delegate from Virginia, while pro-Trump delegates tried to drown out the rebels with shouts of "Shame! Shame!" This was meant to be Trump's moment.
Heading into the four-day political jamboree at the tightly secured arena in Cleveland, he had tried to assuage conservative critics and bring the party together by naming Indiana Governor Mike Pence as his running mate.
Trump was expected later in the day in Cleveland, where his wife Melania Trump, a Slovenian-born former model, has top billing for the first prime-time session and will make the case for her husband's policies and personality.
But Monday's floor protest raises serious questions about Republican unity heading into the November election.
The tough-talking real estate mogul's rise to the top of the Republican party has been one of the more improbable journeys in American politics.
Trump's opponents had little chance of stopping his march. But with an eye on history, many wanted a floor vote to record for posterity who backed the 70-year-old Trump and those who did not.
"We're here to be delegates not rubber stamps," said Regina Thomson a delegate from Colorado.
Trump fans argue delegates should heed the will of the grassroots of the party.
The billionaire won a thumping victory in a series of statewide party elections, winning more than 13 million votes - the most of any Republican nominee ever.
Hours earlier, Republican National Committee chairman Reince Priebus told thousands of cheering delegates: "This convention will come to order."
A string of speakers then recited familiar conservative credos and lambasted their Democratic nemesis Hillary Clinton.
Team Trump has given the dissenters short shrift.
"This is a Trump convention. The party is united," Trump campaign chair Paul Manafort said curtly before the gathering began.
But in a sign of lingering divisions, several party luminaries are not making the trip to Cleveland, including the entire Bush family, Mitt Romney and reportedly even John Kasich, host state Ohio's sitting governor.
Polls show that Trump struggles badly with moderate voters, and his campaign will want to project a more positive image to the general electorate.
Melania Trump's background and allure make her a potentially potent surrogate for her White House hopeful husband, particularly on sensitive issues like immigration and gender.
After his wife, the candidate's team will send his son and daughters to the convention stage in the coming days in an attempt to humanize The Donald.
The opening-day theme was meant to be "Make America Safe Again" - a play on Trump's slogan "Make America Great Again."
A spate of race-tinged police-involved shootings - and cop killings, including the fatal shooting of three officers in Louisiana on Sunday - has put the country on edge.
Deadly attacks overseas, most recently in Nice, and an attempted coup in Turkey, have only stoked an overall sense of instability.
President Barack Obama has urged Americans to temper their words and show stronger common resolve, but Trump is instead highlighting divisions.
"Our country is divided and out of control. The world is watching," Trump tweeted shortly after the Baton Rouge shooting.
Trump has portrayed himself as a sheriff who can fix things.
"We have to bring law and order back to this country, whether we like it or not," he told Fox, as he bemoaned the ragged state of race relations in America.
Trump argues that Clinton should be jailed for using a private email server to handle sensitive government documents while serving as secretary of state, something the FBI said was careless but not criminal.
As the GOP convention kicked off, Clinton blasted Trump's candidacy as a "threat to our democracy," and accused him of stoking racial and ethnic tensions with his rhetoric.
Trump "plays coy with white supremacists, Donald Trump insults Mexican immigrants," she told the NAACP, America's largest black civil rights organisation, at a meeting in Cincinnati.
"Donald Trump cannot become president of the United States," she said, to huge applause.
The Republican convention ends Thursday with a speech from the 70-year-old billionaire real estate mogul. The Democrats stage their own convention next week in Philadelphia.