US President Donald Trump, who is trying to persuade voters that his challenger Joe Biden will encourage violent crime, has retweeted a faked video purporting to show the Democrat playing a crudely worded anti-police rap song.

In the video, which Twitter later marked as "manipulated media", Mr Biden stands at a podium, takes out his mobile phone and tells the audience, "I have just one thing to say."

He then appears to play NWA's 1988 protest song "F*** tha Police" and dances slightly, smiling.

After a few seconds, he jokes: "If I had the talent of any one of these people, I'd be, I'd be elected president by acclamation."

"China is drooling," Mr Trump writes over the retweet.

The problem is that Mr Biden did not play NWA's song.

The footage is taken from a campaign trip to Florida on Tuesday, where Mr Biden took out his phone and played a few seconds of "Despacito."

The Latin hit's singer, Luis Fonsi, had just introduced Mr Biden at the event.

Mr Trump has made his claim that he is keeping America safe from left wing mobs a keystone of his re-election campaign. Polls show he is currently behind Mr Biden.

On Tuesday, Mr Trump shared a supporter's tweet that portrays Mr Biden as a paedophile.

A Reuters/Ipsos poll shows that Mr Biden leads Mr Trump nationally among likely US voters by 9 percentage points, highlighting that Mr Trump's "law and order" message falling short with its target audience of suburban voters.

The opinion poll taken between 11-15 September, released today, found that 50% of likely voters said they were casting their ballots for Mr Biden while 41% were doing the same for Mr Trump.

Another 3% said they would support a third-party candidate and the rest were undecided.

The poll also showed that most American voters were locked in on their choice for president.

Nine out of 10 likely Biden voters and 8 out of 10 likely Trump voters said they were "completely certain" about their choice for president.

Only 1 in 10 likely Biden voters and fewer than 2 in 10 likely Trump voters appeared to be wavering in their choice.

The poll suggests that Biden has an early advantage in securing the national popular vote in the 3 November presidential election.

Still, 9% of likely voters are undecided or have not yet supported either major-party candidate. Their decision incoming weeks could determine who wins.

Winning the national popular vote does not necessarily mean winning the election, which is decided by the state-by-state Electoral College system. Mr Trump won in 2016 despite losing the popular vote.

Mr Trump, who has trailed Mr Biden in most national surveys this year, has spent recent months trying to refocus his campaign on the anti-racism protests that have spread across the country following the killing of African Americans including George Floyd in confrontations with police.

Mr Trump has tried to position himself as a protector of the"Suburban Lifestyle Dream," saying that suburban Americans want safety and security more than anything else.

The Reuters/Ipsos poll found that only 11% of suburban whites said the most important factor driving their vote was a candidate's perceived interest in being "tough on crime" and civil unrest.

That is down from 13% of suburban whites who responded to a similar poll that ran 9-10 September, and 15% who said the same thing in a 3-8 September poll.

Instead, suburban whites, like all Americans, have been largely driven by concerns about the coronavirus, which has killed more than 195,000 people so far in the United States,more than any other country in the world.

When asked about the most important factor driving their vote, 27% of suburban whites said they were looking for a candidate with a robust plan for handling the virus, while 25% said they wanted someone who would restore trust in American government.

Another 19% said they wanted a president who was strong on the economy and jobs.

Mr Trump is now planning to spend $10m on advertisements that focus on the economy - an issue where he maintains a high level of popularity.

The poll found that 45% of US adults think Mr Trump is the better candidate for rebuilding the economy, compared with 36%who say Mr Biden would be better.

Overall, battling the coronavirus ranked as the number one concern and restoring trust in government number two.

The Reuters/Ipsos poll was conducted online, in English ,throughout the United States. It gathered responses from 1,358 American adults, including 859 likely voters. The poll has a credibility interval, a measure of precision, of about 4 percentage points.