Donald Trump made a surprise appearance on the first night of the Republican Party convention Monday, one day before he was to be formally nominated as the party's presidential candidate.

"We're going to win, we're going to win so big," Trump said, basking in cheers from the delegates as he appeared on a darkened stage silhouetted against a lighted doorway.

Trump appeared to introduce wife Melania, who was giving the main speech on the first night of the four-day convention.

Melania Trump declared her husband "ready to serve and lead this country as the next president of the United States."

She was the first of several family members to speak as the campaign seeks to reintroduce its presidential candidate to voters both inside and outside the conservative party.

"He is tough when he has to be, but he is also kind and fair and caring," she said as the campaign tries to humanize the billionaire businessman. "This kindness is not always noted, but it is there for all to see. That is one reason I fell in love with him to begin with."

The theme of Monday evening's speeches was Make America Safe Again, with speaker after speaker painting Trump as a tough leader who would protect Americans by taking on Islamist terrorists, illegal immigrants and criminals.

"Today our allies no longer trust us, our adversaries no longer fear us, and our enemies are plotting against us. This did not happen by accident, it happened by design," Congressman Mike McCaul, who heads the House Homeland Security Committee said, pointing to the work of President Barack Obama and his former secretary of state and would-be successor Hillary Clinton.

"For years they presided over America's retreat. And the consequence is clear: Leading from behind has led us into danger."

The campaign sought to draw a contrast with presumptive Democratic nominee Clinton by prominently featuring the mother of one of the US citizens killed in the 2012 terrorist attack on the US consulate in Benghazi, Libya, during her tenure as secretary of state.

Several speakers described how their family members had been killed by illegal immigrants or in an attack at what they described as the unsecured US border with Mexico, where Trump has vowed to build a wall to halt illegal crossings.

Indiana delegate Dana Carroll told dpa she liked Trump's "brash attitude" and said she though he would "lead us back to where we should be."

The Trump campaign had to win over not just US voters at large, but even many of the party faithful within the arena, as the party remains divided after a fractious primary process that saw the unexpected rise of outsider Trump.

An analysis by Pew Research Centre found that most Republicans had changed their minds at least once in their choice for president. As late as April some 44 per cent did not support him, but now 88 per cent do.

A minority of delegates had held out hope until Monday that they could force the convention to consider an alternate nominee, in a throwback to earlier days when the party's delegates had a greater sway than under the current system of state-by-state primary elections.

The Trump campaign has dismissed the push, and chose vice presidential candidate, Indiana governor Mike Pence, to seek party unity with more traditional Republicans.

"Of course he's going to win: This is a Trump convention," campaign chairman Paul Manafort said. "This party is united."

Chairman Reince Preibus called the Republican National Convention into session as delegates from across the United States prepare to nominate Trump for the November general elections.

Events began Monday as delegates approved the rules for the proceedings and a party platform that bears the distinct mark of Trump, backing away from the Republicans' strong support for free trade and calling for the construction of a wall along the US-Mexican border.

The traditionally staid business proceedings however saw early fireworks as a small group of Republicans opposed to Trump's candidacy tried unsuccessfully to disrupt the proceedings and call for delegates to pick an alternate candidate.

The party's 2,472 delegates are to officially put forward the presidential nominee on Tuesday. The winner needs 1,237 delegates, and Trump cleared that hurdle in May.

Related stories

Latest news

Syrian opposition rules out future role for President al-Assad

The Syrian opposition said Friday it would not accept any role for President Bashar al-Assad in the future of the war-torn country, reacting to a recent US shift saying that removing al-Assad is no longer a priority for Washington.

Russian Army integrates breakaway forces of Georgian province

Parts of the small fighting forces of the Georgian breakaway province of South Ossetia have been placed under Russian military control, Russian Defence Minister Sergei Shoigu said on Friday.

Czech Republic's Pilsner Urquell beer is now Japanese

Japanese brewing company Asahi completed its takeover of the Czech brewery Pilsner Urquell on Friday, Asahi said in a statement.

Judge approves 25-million-dollar settlement of Trump University case

A US district judge on Friday approved a 25-million-dollar settlement of lawsuits and state fraud allegations against Trump University, the US president's now-defunct business venture.

Former Thai premier Thaksin to junta on reconciliation: 'Cut me out'

Former Thai prime minister Thaksin Shinawatra on Friday announced that he is not interested in the junta-led reconciliation process, three days after the junta handed him a half-a-billion-dollar tax bill for his past business deal.

Dalic: We welcome possible deal between Agrokor and banks

The government welcomes the possibility of an agreement being concluded between the Agrokor food company and creditor banks, and the bill on vitally important companies is not a fallback plan but the result of the government's care for the overall economic and financial stability of Croatia, Deputy Prime Minister and Minister of Economy Martina Dalic told a press conference in Zagreb on Friday.

Croatia, China sign action plan for cooperation in agriculture

The Croatian and Chinese ministries of agriculture on Friday signed an action plan for cooperation in the field of agriculture for the period 2017-2018, the Croatian ministry said in a statement.

ZSE indices up, Agrokor shares in focus of investor interest

The Zagreb Stock Exchange (ZSE) indices on Friday rose by more than 1.8%, with stocks of the Agrokor food and retail concern being in the focus of investor interest again.

Berlin police defend handling of Berlin market attacker

Berlin police defended themselves on Friday against accusations that they stopped surveillance on Berlin Christmas market attacker despite knowing in June 2016 he was dangerous.

Croatia, creditors tailor emergency measures to save tottering giant

Croatia's tottering retail and food giant Agrokor reached an agreement with its creditors, putting its debts standby and allowing it to continue working during emergency restructuring, the Croatian branch of Austria's Erste Bank said Friday.

Agrokor's creditors say standstill agreement to go into force today

A standstill agreement regarding the Agrokor concern's existing financial obligations to banks will take effect on Friday, additional capital will be injected into the concern in the coming days and the concern will be actively restructured, which includes a change of its management, it was said on Friday after a meeting between Agrokor's suppliers and creditor banks.

Palestinians, UN slam Israel's new settlement plan

Palestinians, Israeli activists and the UN lambasted the government of Israeli Prime Minister Benjamin Netanyahu on Friday, a day after it gave the go-ahead for the first new West Bank settlement in a quarter of a century.

South Sudan rebels release three abducted foreign oil workers

South Sudanese rebels have released three foreign engineers they abducted in early March in the oil-rich Upper Nile region, Foreign Affairs Ministry official Mawein Makol Arik said on Friday.

Turkish opposition: Imprisoned party chief has gone on hunger strike

The head of Turkey's pro-Kurdish opposition party has launched a hunger strike from prison.

European leagues threaten Champions League schedule clashes

The European Professional Football Leagues (EPFL) on Friday threatened schedule clashes on Champions League matchdays in an ongoing dispute with the governing body UEFA.

Danish court revokes citizenship of IS volunteer

A Danish appellate court on Friday stripped a man of his Danish citizenship for volunteering to fight for the extremist Islamic State in Syria.

Banks and Agrokor agree on key elements of standstill agreement

Member banks of the coordinating committee of financial creditors and representatives of the Agrokor food company have in principle agreed on key elements of a standstill agreement, which is expected to be signed later today, announcing changes in the company's management team, Erste Bank said in a statement on Friday afternoon.

Syrian man on trial in Sweden; mosque attack labelled terrorism

A Syrian man went on trial Friday in the southern Swedish city of Malmo, charged with terrorism and arson after an attack last year on a building used as an assembly hall by Shiite Muslims.