Conservative mainstay Breitbart News is in turmoil over Donald Trump.

Reporter Michelle Fields and at least three other staffers have resigned in opposition to their company's coverage of Trump and to its handling of an alleged assault on Fields by a top Trump aide.

Fields, who has claimed that she was yanked and bruised by Trump campaign manager Corey Lewandowski, and Ben Shapiro, one of the site's top editors, told BuzzFeed late Sunday night that they would be leaving the company.

Then on Monday, Breitbart editor Jarrett Stepman and national security correspondent Jordan Schachtel announced they were also resigning in protest.

"Today I informed the management at Breitbart News of my immediate resignation," Fields said on Sunday. "I do not believe Breitbart News has adequately stood by me during the events of the past week and because of that I believe it is now best for us to part ways."

In his own statement, Shapiro said that Breitbart News had become Trump's "personal Pravda," referring to the communist newspaper.

Stepman similarly said he believed Breitbart News "is becoming less of a news site and more of a propaganda organization dedicated to the Trump campaign." Schachtel wrote that he had signed up to be a journalist, not "a member of the Donald J. Trump for President media network."

The announcements came after a week in which Breitbart News appeared to side with the Trump campaign's version of events over that of Fields.

Fields, who has also brought criminal charges against Lewandowski, claims that he grabbed her and bruised her arm while she was trying to ask Trump a question after his press conference last Tuesday night.

Related: Breitbart reporter says she filed charges against Trump's campaign manager

Trump, Lewandowski and the campaign dispute that, and say no such incident ever took place. "This was, in my opinion, made up," Trump told CNN after Thursday night's Republican debate. "Everybody said nothing happened. Perhaps she made the story up. I think that's what happened."

On Friday, Breitbart published a video of the moments just before the incident and claimed the video provided evidence that it was not clear that Lewandowski actually pulled Fields -- a move that struck many observers as evidence of the site's pro-Trump bias. (Especially when, hours later, the Daily Beast published a video from the rally that appeared to show Lewandowski reaching out toward Fields' arm.)

In his statement Sunday, Shapiro argued that Breitbart chairman Steve Bannon had betrayed the mission of the site's founder, the late Andrew Breitbart.

"Andrew's life mission has been betrayed. Indeed, Breitbart News, under the chairmanship of Steve Bannon, has put a stake through the heart of Andrew's legacy," Shapiro wrote.

"In my opinion, Steve Bannon is a bully, and has sold out Andrew's mission in order to back another bully, Donald Trump; he has shaped the company into Trump's personal Pravda, to the extent that he abandoned and undercut his own reporter, Breitbart News' Michelle Fields, in order to protect Trump's bully campaign manager, Corey Lewandowski, who allegedly assaulted Michelle," Shapiro wrote.

These departures come just days after Kurt Bardella, the site's spokesperson, resigned from his position because he felt he could no longer serve an organization that was putting the interests of the Trump campaign ahead of its own reporter.

"When you reach a point where you can't give 100% to people you represent, it's not tenable to continue representing them," Bardella said in a statement. "My own personal observation is that there is a cycle of behavior that is escalating and it's happening exclusively at Donald Trump events. It is wrong, disgusting and indicative of an ugliness that is contaminating the public and political discourse in our country."

"Life is too short to invest your time in things you don't believe and aren't passionate about," he continued. "That is why I made the decision to resign from representing Breitbart."