An American Airlines flight was urgently diverted after a passenger assaulted a flight attendant, authorities have reported.
Flight 976 departed from New York's John F. Kennedy International Airport and was supposed to arrive at John Wayne Airport in Santa Ana, California.
Instead, the plane landed at Denver International Airport. Once the passenger was removed, the flight continued to California.
Reports say the flight attendant was taken to hospital but details on her condition were not immediately available.
American Airlines said the behaviour was unacceptable.
"We are outraged by the reports of what took place on board. Acts of violence against our team members are not tolerated by American Airlines," the Texas-based airline said in a statement.
Aside from banning the passenger from American Airlines flights, the airline also said they would "not be satisfied until he has been prosecuted to the full extent of the law. This behaviour must stop."
A fellow passenger on the flight, Mackenzie Rose told CBS Los Angeles that the assault happened around halfway through the trip, while flying over Ohio.
"I understand that he actually punched her twice," Rose said.
"I did see her walk back down the aisle afterwards. She had blood splattered on the outside of her mask."
The assault is part of a concerning trend of unruly airline passenger behaviour.
Some rampages have even been caught on popular social media platforms such as tiktok and gone viral.
The US Attorney's Office in Colorado and FBI said an investigation was underway and the Federal Aviation Administration said they would also investigate.
FBI spokesperson Courtney Bernal said no arrests had been made as of Thursday.
"The United States Attorney's Office takes seriously all matters involving potential threats to the safety of airline flights, crew or passengers," a statement said.