CHICAGO, April 10 (Xinhua) -- United Airlines CEO Oscar Munoz apologized Monday for having to "re-accommodate" the customers in an overbooked flight after videos showing an Asian man dragged from his seat in an United flight, which sparked wide-spread criticism on social media.

"This is an upsetting event to all of us here at United," Munoz said in the statement, adding the United is "reaching out to this passenger" and "further address and resolve this situation."

Earlier, videos on social media showed an Asian man was dragged forcibly from his seat on a flight by three security officers, causing the man to scream in agony. The officers then dragged the man along the aisle, with his glasses askew and his shirt above his abdomen. Other pictures taken at the same flight showed the man had blood near his mouth.

According to Chicago Tribune, the incident happened on an United flight at Chicago's O' hare international airport Sunday evening. United Airlines had the flight overbooked and asked for four volunteers to give up their seats to United employees, after everyone was already boarded.

When no one answered, United Airline announced that they would draw volunteers randomly by computer. One passenger was drawn, but he refused to leave. The United employees called security, who then dragged the passenger from his seat and off the plane.

Videos taken by other passengers on the same flight drew more than a million hits on social media, with many criticizing United Airline's handling of the incident.