"How do you know those bruises weren’t there before?" he said. "If you’re going to get squeezed, wouldn’t you let out a scream or something? How did they get there? Who put them there?"
The businessman added that Lewandowski only confronted Fields when the reporter would not stop questioning him after a press conference ended.
“She’s grabbing at me, and he’s acting as an intermediary and trying to block her from doing that," he said. "Maybe he was trying to get her off me. The news conference was done and I was leaving. ... There are pictures where she's grabbing my arm and I'm going like this, trying to get her off," Trump told reporters, raising his right elbow to demonstrate.
Trump appeared to be referring to a photo he tweeted moments earlier showing his right elbow elevated next to Fields.
However, video released by police shows that Trump made the gesture with his elbow while reaching into his left coat pocket to retrieve a writing device.
Trump is seen in video stopping for a moment to apparently sign a book in his left hand while Lewandowski had his hand on Fields's arm behind him.
Trump said he doesn't believe Lewandowski is capable of doing what he's accused of.
“If he was that way, I would have fired him in two seconds," he said. "I’m sticking up for a person because I’m not going to let someone’s life be destroyed. No jury would convict a man and destroy his life over that."
Lewandowski was issued a notice to appear in court May 4.
Trump’s GOP rivals seized on the incident as proof that his campaign encourages brutish behavior.
“This is the consequence of the culture of the Trump campaign, the abusive culture, when you have a campaign that is built on personal insults, on attacks, and now, physical violence,” Texas Sen. Ted CruzTed CruzTHE MEMO: Trump takes the fight to Congress Brietbart CEO reveals that Trump donors are part owners At CPAC, Trump lashes out at media MORE told reporters in Wisconsin.
“Campaigns reflect the values of the candidate — I know ours does,” tweeted John Weaver, a strategist for Ohio Gov. John Kasich. “If this bully worked for John Kasich, he would have been fired long ago.”
The Democratic presidential campaigns similarly criticized Trump.
“Every campaign has to be accountable for the culture that they create,” Hillary ClintonHillary Rodham Clinton5 ways politics could steal the show at Oscars Lewandowski: Perez ‘doesn’t understand what’s going on in America’ Five takeaways from the Scott Pruitt emails MORE spokesman Brian Fallon said on CNN.
Bernie SandersBernie SandersLewandowski: Perez ‘doesn’t understand what’s going on in America’ Sanders dodges question on whether he will give email list to DNC Sanders: Ellison ran impressive campaign 'playing inside the establishment's house' MORE campaign manager Jeff Weaver accused Trump’s campaign of encouraging “thuggery.”
“It looks like it pervades the campaign, both among supporters and among staff,” he told CNN's Wolf Blitzer, linking the incident with past violence at Trump rallies.
Liberal group EMILY's List said the incident is emblematic of Trump's long record of misogyny.
"If Trump can’t be trusted to condemn what’s wrong, how can he even begin to comprehend what’s right for women?" Communications Director Marcy Stech said in a statement.
Trump spokeswoman Hope Hicks on Tuesday told The Hill that Lewandowski is “absolutely innocent of this charge” and intends to plead not guilty.
Trump spokeswoman Katrina Pierson said on CNN that Lewandowski would remain campaign manager despite the charge.
Trump drew controversy last week for a series of tweets about Cruz's wife, Heidi.
Trump tweeted a threat to "spill the beans" about Heidi Cruz and later shared an unflattering photo comparing her to Trump's wife, Melania.
The businessman said he was responding to a super-PAC ad that featured a nude photo of Melania. Trump insisted Cruz was connected to the outside group's ad, though he offered no proof.
Cruz responded by calling Trump a “sniveling coward” for dragging his wife into the campaign.
The series of incidents come as the candidates set their sights on Wisconsin's primary next week.
Cruz leads the state over Trump by less than 1 percentage point, according to a RealClearPolitics polling average.
The Texas senator got a boost when Wisconsin Gov. Scott Walker, himself a former presidential candidate, endorsed Cruz earlier Tuesday.
—Updated at 5:29 p.m.