Donald Trump’s election campaign has taken a hit after his campaign manager was charged with battery of a female reporter, after allegations he forcefully grabbed her at a campaign event.

Corey Lewandowski was arrested on March 8, 2016,  after Michelle Fields, reporter for the conservative news outlet Breibart, alleged he had grabbed her arm and bruised her at a public event for Mr Trump’s campaign.

A statement from the Trump camp declared Mr Lewandowski’s innocence and said he was “looking forward” to his day in court.

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“He is completely confident that he will be exonerated,” the statement read.

Trump described Mr Lewandowski as a “fine man”. Photo: Getty

Mr Trump also took to social media to defend his employee, claiming Ms Fields had changed her story after footage was made public.

“Wow, Corey Lewandowski, my campaign manager and a very decent man, was just charged with assaulting a reporter. Look at tapes-nothing there!” wrote Trump, referring to news footage of the campaign event obscured by the busy crowd.

But a separate piece of footage, appearing to show the moment Mr Lewandowski grabbed Ms Fields by the arm to pull her away from Mr Trump, was released by police to the public.

Ms Fields also tweeted an image of a bruised arm, with the caption, “I guess this just magically appeared on me. So weird.”

For a first offence, battery in Florida is a misdemeanour in the first degree, which carries a maximum sentence of one year in prison or a fine of $US1,000 ($A1,320).

Ms Fields resigned from Breitbart less than a week after the incident, citing the reason was the online news outlet’s refusal to stand behind her amid the allegations.

Since the incident, another video has emerged on Twitter, apparently showing Mr Lewandowski pulling the collar of a protestor at a rally.

A court date was set for May 4, according to the police report.

Watch security footage of the incident below:

Busted: @realDonaldTrump campaign manager charged in incident with @BreitbartNews reporter https://t.co/NPXftVgdtx https://t.co/SHApYIz1FO

— NY Daily News Video (@NYDNVideo) March 29, 2016

I guess these just magically appeared on me @CLewandowski_ @realDonaldTrump. So weird. pic.twitter.com/oD8c4D7tw3 — Michelle Fields (@MichelleFields) March 10, 2016

Here is Donald Trump’s campaign manager in the Tucson crowd grabbing the collar of a protester. pic.twitter.com/JZ9RntWlHY — Jacqueline Alemany (@JaxAlemany) March 19, 2016

  – with ABC