CHICAGO -- United Airlines is responding to reports of an incident involving an attendant, saying late Thursday it is "aware of a concerning incident involving a flight attendant serving on our regional service provider Trans States Airlines flight 4689." The statement came after a person who indicated in online posts that she was on the flight posted pictures and cellphone video of a flight attendant looking disheveled and later confronting another passenger.

The person claimed on Twitter she "had to go to the cockpit "and tell the pilot about "an out of control attendant."

Pictures and cellphone video showed a flight attendant looking disheveled and later confronting a passenger. Erika Cooper Gorman

"As a gesture of goodwill, we have compensated all customers aboard the flight and we apologize for any inconvenience or distress this may have caused," United said in a statement.

Get Breaking News Delivered to Your Inbox

Trans States Flight 4689 was headed from Denver to Williston, N.D. Police were reportedly waiting at the airport when the plane landed, CBS Chicago reports.

Trans States Airlines said it is aware of reports of a flight attendant's "erratic behavior" and that the situation is under investigation. It said the flight attendant is being "held out of service."