A parent allegedly attacked a teacher Friday at a California elementary school over a dispute about wearing masks on the first day, NBC reported.

The incident occurred at Sutter Creek Elementary School in Amador County, Calif., when the parent saw his daughter coming out of the building with a face covering and grew frustrated over the school’s mask mandate. The parent reportedly engaged in a verbal altercation with the school principal when a male teacher intervened, causing the situation to escalate.

The alleged physical fight left the teacher bleeding, according to NBC.

“As the first day of school comes and goes, there are always hiccups along the way, especially during this trying time,” Amador County Unified School District Superintendent Torie Gibson wrote in a letter to families.

“Unfortunately, a parent took it upon himself to verbally assault a principal that led to a serious physical altercation between him and a teacher as the teacher intended to protect the principal,” Gibson added.

The teacher suffered “lacerations on his face, some bruising on his a face and a pretty good knot on the back of his head,” according to NBC affiliate KCRA of Sacramento.

Gibson said that “assaulting a staff member will never be tolerated on any school campus” and noted that the mask requirements are constantly changing. 

“We are not the ones making the rules/mandates,” she wrote in the letter. “We are the ones required to follow/enforce them if we want to keep our doors open and students at school five days a week.”

The situation reflects the nationwide debate over mask mandates in schools, which President BidenJoe BidenOn The Money: Federal judge rejects effort to block eviction moratorium | Moderates revolt on infrastructure in new challenge for Pelosi | Consumer confidence plunges in AugustErykah Badu apologizes for being ‘terrible guest’ at Obama’s birthday partyMcConnell calls for US airstrikes to stop Taliban advanceMORE says should not be politicized.

“I know there are a lot of people out there trying to turn a public safety measure that is, children wearing masks in school so they can be safe into a political dispute. But this isnt about politics,” Biden said Thursday. “This is about keeping our children safe.”