SAN JOSE, Calif. (AP) — A Southwest Airlines pilot is under investigation for allegedly assaulting a flight attendant at a California bar during an argument over wearing masks.

USA Today reports the pilot was cited for assault and battery over the Oct. 18 dispute at a hotel bar in San Jose.

The Santa Clara County district attorney's office will determine whether to file criminal charges.

Southwest told CBS News in a statement that it received a report regarding the off-duty disagreement that occurred during an overnight trip. The airline added that it’s conducting an internal investigation into the incident and the pilot has been placed on leave.

The incident comes amid a surge in unruly airline passengers this year, who sometimes become violent.

The FAA says airlines have reported thousands of cases of disruptive passengers, most of them involving passengers who refused to obey a federal requirement to wear a mask.