Donald Trump formally nominated by Republican Party as presidential candidate

The Republican Party formally nominated Donald Trump for president of the United States Tuesday, capping a roller-coaster campaign that saw the billionaire tycoon defeat 16 White House rivals.

"It's my honor to be able to throw Donald Trump over the top in the delegation count tonight," his son Donald Trump Jr told delegates at the Republican National Convention which erupted in cheers and applause.

Trump is expected to formally accept the nomination in a speech at the convention in Cleveland on Thursday, before facing off against Democrat Hillary Clinton in the November election battle.

An instrumental remix of Frank Sinatra's hit "New York, New York" boomed into the arena after the announcement as delighted delegates swayed in time with the music and waved their arms in the air.

"It's unbelievable. It's surreal. I'm so proud of my father. I'm so proud. We all are," Trump's eldest daughter and businesswoman Ivanka, often described as his secret weapon, told CNN.

"It's amazing. He's the ultimate outsider and he did it. We are so proud of him."