Image copyright Getty Images Image caption Mr Trump's campaign has denied there were any instances of plagiarism

The Trump campaign has denied allegations that Melania Trump plagiarised her speech at the Republican National Convention.

Staff said there was no evidence Mrs Trump had lifted passages from a 2008 speech by First Lady Michelle Obama.

The plagiarism accusation loomed large on Tuesday as the convention entered its second day.

Mr Trump is expected to be formally nominated as the Republican Party's presidential candidate.

A last-ditch effort by anti-Trump delegates to hold a vote that would have allowed them to back a candidate of their choices failed on Monday.

Live coverage: Delegates to formally nominate Trump

Why the Melania plagiarism row matters

Twitter mocks Melania

Plagiarism quiz: Who else has been caught out?

Mrs Trump and campaign staffers have given mixed messages on who wrote the speech.

She told NBC's Matt Lauer that she wrote it with some help from others, but the Trump campaign said in a statement shortly following the speech on Monday that "Melania's team of writers took notes on her life's aspirations, and in some instances included fragments that reflected her own thinking".

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

The speech controversy has been "totally blown out of proportion," said Trump adviser Paul Manafort.

"They're not even sentences. They're literally phrases. I was impressed that somebody did their homework to think that could be possibly done."

Republican National Committee chairman Reince Preibus said he "probably" would have fired speechwriters if the same thing had happened to him, but he also called the controversy a "distraction".

Mr Trump's son Donald Jr said of Mrs Trump's speech that there were probably people who "should have cleaned it up better".

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?