CHICAGO, IL — A Chicago airport security officer who helped drag a United Airlines passenger off a plane by his arms, bloodying his lip as horrified passengers protested and recorded the episode on their smartphones Sunday night at O'Hare International Airport, was placed on leave Monday.

The episode aboard United Flight 3411 from Chicago to Louisville has become a national embarrassment for the Chicago Department of Aviation and United Airlines. Millions of people now have seen videos of the screaming man as he was forcibly pulled from his seat by three officers, put to the ground and dragged down the aisle. The man, who said he was a doctor, was among four passengers randomly selected on the full flight to give up their seats for United Airlines employees who needed to be in Louisville by Monday, according to witnesses. As the passenger was pulled down the aisle, one passenger exclaimed, "Can't United rent a car for the (employees) to get to Louisville?" Another passenger pointed out, "You busted his lip" after Chicago airport police grabbed him. Several videos were posted to social media. In one, blood can be seen forming on the man's lip and his eyeglasses are askew.



The petrified, disoriented man, who managed to get back on the plane before being taken to the hospital, ran down the aisle shouting, "I have to go home." As he stood at the back of the plane, he said, "just kill me ... just kill me." Police said the man was taken to Lutheran General Hospital in Park Ridge for treatment to his injuries. #flythefriendlyskies @united no words. This poor man!! pic.twitter.com/rn0rbeckwT

— Kaylyn Davis (@kaylyn_davis) April 10, 2017 Monday morning, United CEO Oscar Munoz issued a brief statement calling the incident "an upsetting event."

"I apologize for having to re-accommodate these customers," Munoz said. "Our team is moving with a sense of urgency to work with the authorities and conduct our own detailed review of what happened." Later in the day, Munoz sent a lengthy letter by email to United employees praising and defending them.

"Our employees followed established procedures for dealing with situations like this," Munoz said in the email, which was posted to social media. "While I deeply regret this situation arose, I also emphatically stand behind all of you, and I want to commend you for continuing to go above and beyond to ensure we fly right."

Munoz said United's investigation of the episode shows the man was approached "politely" and asked to deplane but he became "disruptive and belligerent" and forced security to act. The Department of Aviation issued a statement about its officers' actions Monday afternoon — and the city was neither praising nor defending what happened on the plane.

"The incident ... was not in accordance with our standard operating procedure and the actions of the aviation security officer are obviously not condoned by our Department. The officer has been placed on leave effective today and pending a thorough review of the situation."