Donald Trump says Michelle Fields deserved to be manhandled by campaign manager Corey Lewandowski

Donald Trump defended his campaign manager who has been charged with misdemeanour battery after he was captured on videotape grabbing the arm of a reporter.

Corey Lewandowski was protecting his boss from then-Breitbart reporter Michelle Fields when he forcefully grabbed her arm at a news conference at the Trump National Golf Club in Jupiter, Florida, Trump insisted to the media hours after his campaign manager was charged.

"Corey's a fine person," Trump said. "I looked at the tape and ... she was actually — if you look at her, and according to a lot of people — she's grabbing at me. And [Corey] is acting as an intermediary and trying to block her from doing that."

Fields was "running up and grabbing and asking questions and she wasn't supposed to be doing that," he said. "There are pictures where she's grabbing my arm." The "press conference was over," he added.

Trump said the charges against his top aide are "very unfair" and Lewandowski has been "very, very seriously maligned" by critics. He also indicated that Fields had lied about the bruises that appeared on her left arm after the incident. "How do you know those bruises weren't there before?" he asked reporters.

Police don't agree with Trump's assessment of the situation. Lewandowski was charged with simple battery after police released surveillance videos showing the campaign manager grabbing Fields' arm and yanking her back as she walks alongside Trump apparently asking questions during the 8 March event.

After Fields complained about the incident, Lewandowski responded in a tweet: "You are totally delusional. I never touched you. As a matter of fact, I have never even met you."

Lewandowski was issued notice to appear in court on the battery charge. The New York City resident is expected in Palm Beach County Circuit Court in early May, the Palm Beach Post reports.

In a bizarre addition to the incident, Trump mockingly read Fields' statement at the CNN Republican Town Hall meeting. He quoted her as saying she was yanked by his campaign manager and almost fell, but Trump added: "Give me a break." Trump also said the pen in Fields' hand could have been "a little bomb."

He read the statement after journalist Anderson Cooper questioned him about Lewandowski "blatantly lying" about not touching Fields, when it was clear on the tape that he had. Fields reportedly left Breitbart after the confrontation, saying the news outlet hadn't stood up for her after the incident.

Ben Shapiro - the former Breitbart editor-at-large - also resigned, claiming that the conservative news outlet - seen largely as supportive of Trump's presidential bid - "abandoned" Fields "in order to protect Trump's bully campaign manager."