An angry parent allegedly ripped off a teacher's mask. It's not the only physical altercation over masks in schools.

A parent in Austin, Texas has been accused of physically assaulting a teacher during a back-to-school event – over mask wearing. It's not the only incident of its kind. Several incidents at schools and local school board meetings have gained national attention as debates over mask requirements turn heated, some of them resulting in physical violence.

Superintendent Tom Leonard of Austin's Eanes Independent School District confirmed in a letter to parents and staff this week that a parent "physically assaulted a teacher by ripping a mask off her face," at a "Meet the Teacher" event. Leonard said other parents yelled "at a teacher to take off her mask because they could not understand what the teacher was saying while her face was covered."