DECATUR, Ill. -- Sen. Ted Cruz (R-Texas) weighed in on allegations against Donald Trump 's campaign manager, who allegedly assaulted a reporter last week, calling the behavior a "fireable offense."

"Of course it's not appropriate," Cruz said in response to a question from a reporter ahead of his fourth event of the day on Monday in Illinois. "What a bizarre world we're in, where reporters are forced to ask the question, 'Should political campaign staffers physically assault reporters?'"

Former Breitbart reporter Michelle Fields accused Donald Trump campaign manager Corey Lewandowski of grabbing her at a press conference in Florida last week when she tried to ask the GOP front-runner a question about affirmative action. Fields, along with Washington Post reporter Ben Terris, say Trump's 41-year-old campaign manager yanked her out of the way, his grip imprinting finger-shaped bruises on her arm.

Even after several videos and recordings of the incident surfaced, the Trump campaign has denied it happened, with Lewandowski taking to Twitter to call Fields "totally delusional" for the accusation. After the GOP debate in Miami last week, Donald Trump told reporters he thought Fields had "made up the story." Fields and several other Breitbart employees resigned in protest of how the news organization handled the incident.

"I remember some months ago we were all amazed and joking about the fact the Hillary Clinton campaign used ropes to hold back reporters, to keep them away from Hillary Clinton, and that seemed like the height of the disdain from a candidate for reporters and the media," Cruz said Monday. "We never envisioned that it would now reach the levels of allegations of significant physical assault. Physically assaulting a reporter is a fireable offense and at the end of the day, the responsibility for any campaign rests with the candidate."

Since the incident, Trump's campaign has come under fire for violence at his campaign events .

Sen. Marco Rubio (R-Fla.) also had strong views on how the campaign handled the situation.

"If my campaign manager had done that, my campaign would be over," Rubio said . "He would have had to resign, and my campaign may be over. I would have had to quit that very day."