Media playback is unsupported on your device Media caption James Cook on how Donald Trump become the Republican Party candidate for US president

Donald Trump has secured the Republican nomination for US president on day two of the Republican National Convention.

The House Speaker, Paul Ryan, urged delegates to unite behind Mr Trump, a day after splits in the party were evident as the convention opened.

The Trump campaign also faces accusations a speech by Mr Trump's wife Melania on Monday was plagiarised.

Tuesday's speakers focused almost exclusively on attacking Hillary Clinton, the likely Democratic nominee.

New Jersey Governor Chris Christie, a former prosecutor, held a mock trial for Mrs Clinton as the crowd chanted "lock her up".

Mr Christie and others criticised Mrs Clinton's use of a private email account while she was serving as secretary of state.

An FBI investigation said she was "extremely careless" but found her actions didn't warrant criminal prosecution. However, Mr Christie and and the crowd disagreed as Mr Christie repeatedly yelled "guilty".

He said she has "selfish, awful judgement" and was to blame for various foreign policy problems in Libya, Syria and elsewhere.

As it happened: Clinton dominates day two

Under the skin of Trump country

Why the Melania plagiarism row matters

Republicans react to Melania 'distraction'

Image copyright Reuters Image caption Mr Trump's adult children led the New York delegation at the convention

Image copyright Getty Images Image caption The crowd repeatedly chanted "lock her up!"

Mr Trump is expected to accept the nomination on Thursday.

His children played a prominent role on Tuesday, standing with the New York delegation as he was declared winner and delivering remarks.

At the scene - Anthony Zurcher, BBC News, Cleveland

Image copyright Getty Images Image caption Mr Trump's takeover of the Republican Party is complete

The result hasn't really been in doubt for months, but now it's a reality. The Republican Party's nomination for president of the United States is Donald Trump's to accept when he takes the stage on Thursday night.

Thanks to a bit of procedural manoeuvring, it was New York that gave him the winning margin in the state-by-state roll call vote. His oldest son, Donald Trump Jr, voice wavering with emotion, made it official.

"Congratulations, Dad, we love you," he said.

As a band blared the song New York, New York, the jumbo screens in this converted basketball arena proclaimed "Over the Top" with exploding gold fireworks.

Perhaps there was no more fitting way to announce the elevation of the latest Republican standard-bearer, the real-estate mogul who confesses to being a bit "braggadocious" and whose rise has roiled the party establishment and turned conventional wisdom on its head.

A tough general election fight against Hillary Clinton awaits. Conventional wisdom is the odds are long, but they aren't any more remote than what Mr Trump has already overcome to get to this point.

Mr Trump youngest daughter, Tiffany Trump, whose mother is former model and dancer Marla Maples, told some personal stories about her father.

She recalled scribbling notes in her school report cards and how excited she becomes when introducing him to her friends.

Her father is a "natural-born encourager" who has motivated her to work hard, she said.

Image copyright AP Image caption Mr Trump's youngest daughter Tiffany said her father had helped her through difficult times

His son Donald Trump Jr described him as his best friend and role model.

"When people tell him it can't be done, that guarantees it will get done," he said of his father.

He said Mrs Clinton was a risk the US could not afford to take and that "if she were elected, she would be the first president who can't pass a background check".

Mr Trump addressed the audience via a live-stream and said the nomination was an honour.

"This is a movement, but we have to go all the way," he said. "This is going to be a leadership that puts American people first."

Parts of Donald Trump Jr's speech used segments of an article that had already appeared in the journal The American Conservative.

But the article's author, FH Buckley, said it was not plagiarism, as Mr Buckley himself acted as one of the family's speechwriters.

Media playback is unsupported on your device Media caption Did Melania Trump's speech copy Michelle Obama's?

After speaking at the convention on Monday, Melania Trump, the mogul's third wife, faced accusations that a portion of her speech plagiarised Michelle Obama.

But Mr Trump's team said she used "common words" and accused the Clinton campaign of stoking the controversy.

On Monday, anti-Trump delegates failed in their final push to block his nomination.

A vote that would have allowed delegates to back a candidate of their choice was quashed when three states reportedly backed out.

Some said the Republican Party officials had sabotaged their efforts on purpose.

A convention - all you need to know

Media playback is unsupported on your device Media caption What's the point of a party convention anyway?

1. What's the point? Each party formally nominates its candidates for president and vice president, and the party unveils its party platform, or manifesto.

2. Who is going? There are 2,472 delegates attending, selected at state and congressional district conventions, and representing each US state and territory. Plus 15,000 journalists and thousands of other party grandees, lawmakers and guests.

3. Who isn't going? Some senior figures who don't like Donald Trump have stayed away, including two ex-presidents named Bush, former nominee Mitt Romney and Ohio Governor John Kasich.

4. What's the schedule?