The social media storm prompted by footage of United Airlines forcibly removing a passenger from an overbooked flight continued to spread on Tuesday with accusations of perceived racism and calls for a boycott of the US carrier.

Footage from the incident in which a Chinese-American passenger was dragged from his seat quickly went viral with outrage extending even to China.

The incident occurred Sunday on a United Express flight from Chicago to Louisville, Kentucky. Such flights are operated by one of eight regional airlines that partner with United.

The airline said it had asked for volunteers to give up their seats, and police were called in after one passenger refused to leave the plane.

Smartphone video posted online showed three Chicago Department of Aviation police officers struggling with a seated middle-aged man.

He starts to scream as he is dragged off while other passengers look on — some recording the event with their phones. One passenger can be heard yelling, “Oh my God, look at what you did to him!”

The showdown quickly ignited social media outrage, with “United” a trending term on Twitter, Facebook and Google.

The footage was also re-posted on China’s Twitter-like Sina Weibo, where the incident quickly became the top trending topic, garnering more than 120 million views and 80,000 comments.

“Shameless! We won’t forgive them. Ethnic Chinese around the world please boycott United Airlines!” wrote one commentator.

United Airlines claims to be the biggest carrier to China, with more nonstop US-China flights to more Chinese cities than any other airline, according to the company’s website.

In a statement late Monday, the Chicago Department of Aviation said the incident was “not in accordance with our standard operating procedure and the actions of the aviation security officer are obviously not condoned by the department.” “That officer has been placed on leave effective today pending a thorough review of the situation,” the statement said.

Speaking to various media outlets about Sunday’s incident, the airline said it had asked for volunteers to leave the overbooked plane.

“One customer refused to leave the aircraft voluntarily and law enforcement was asked to come to the gate,” United spokesman Charlie Hobart was quoted by the Chicago Tribune newspaper as saying.