Florida police have charged the campaign manager for Republican presidential candidate Donald Trump with battery, for allegedly assaulting a journalist at a Trump campaign rally earlier this month.

Corey Lewandowski, 42, is accused of bruising the arm of journalist Michelle Fields, by grabbing her and pulling her backwards as she tried to ask a question of the Republican front-runner as he was walking out of a campaign rally in the town of Jupiter.

In conjunction with the announced criminal charge, police also released a video showing the altercation between Lewandowski and Fields. The video shows Fields walking alongside Trump when Lewandowski grabs her arm from behind and pulls her backward, while Trump continues to walk ahead.

Still, the Trump campaign denies the charges against its campaign manager.

"Mr. Lewandowski is absolutely innocent of this charge," Trump's campaign said in a statement. "He will enter a plea of not guilty and looks forward to his day in court. He is completely confident that he will be exonerated."

Trump's rallies have been marked by growing tension and violence in recent weeks, as the real estate magnate and celebrity TV personality solidifies his hold on the Republican nomination.

The simple battery charge against Lewandowski, as a first time offence, carries a maximum sentence of a year in prison and/or a $1,000 (890 euros) fine.

The altercation provoked a firestorm of recriminations, first and foremost because Fields had been covering the Trump campaign for the archly-conservative online site, Breitbart.

The website disavowed their own reporter's claim, even posting a story online suggesting that it was a case of mistaken identity (Lewandowski's), that is until video footage of the incident appeared.

The management's failure to support their own reporter prompted Fields, and at least five other Breitbart staff members, to resign. In announcing their departures, some said they joined the website to be journalists, not shills for a poltical campaign.

Justs days after the alleged assault, Trump told CNN that the incident was probably "made up." Campaign spokeswoman Hope Hicks went further, saying in a statement then that "not a single camera or reporter of more than 100 in attendance captured the alleged incident."

Since then, of course, multiple video and eyewitness accounts have emerged.

Lewandowski has retained a Florida attorney who said Tuesday there
would be no further comment.

(Reuters, AP)