United Airlines' CEO finally apologized late on Tuesday for an incident in which a passenger was violently removed from an overbooked flight. The apology came only after an overwhelming outcry on social media and a call to boycott the company.

"I continue to be disturbed by what happened on this flight and I deeply apologize to the customer forcibly removed and to all the customers aboard," said United chief Oscar Munoz. "We take full responsibility and we will work to make it right."

Read: United Airlines incident spotlights air traveler rights

On Sunday, United Airlines overbooked its Flight 3411 from Chicago to Louisville. The practice is a common one used by airlines to maximize their revenue in case of no-show passengers. In order to make space for four stand-by crew members, United demanded four people voluntarily leave the plane in exchange for a monetary incentive.

Video goes viral

When no one volunteered, the crew ordered 69-year-old David Dao to vacate his place. Dao refused, explaining he was a doctor with urgent appointments in Louisville the next day. Next, as seen in footage that went viral, Dao was violently dragged from the plane, injured and bloodied by security personnel while the other passengers shouted their dismay.

Technically, passengers are legally required to follow the orders of the captain when they are ordered off a plane. In an initial statement that drew a torrent of criticism, Munoz concentrated on this aspect of the incident and not on the violence inflicted upon Dao.

"Our employees followed established procedures for dealing with situations like this," the CEO wrote in his first comments, saying that United was sorry that some passengers had to be "re-accomodated."

US government dismayed

The incident has highlighted a need for clearer guidelines on the rights of airline passengers. US Congresswoman Jan Schakowsky, a Democrat from Illinois, announced that she was considering introducing legislation to protect passengers from be involuntary removed from airplanes.

The White House also said it was disturbed the event. "When you watch the video, it is troubling to see how that was handled," said Press Secretary Sean Spicer.

Munoz said late Tuesday that United would conduct a "thorough review" of its procedures in order to prevent another similar incident.

Dao's laywer Stephen Golan said that the injured man was in a Chicago hospital receiving treatment. He did not comment on what legal action the family may pursue.

"The family of Dr. Dao wants the world to know that they are very appreciative of the outpouring of prayers, concern and support they have received," Golan said.

es/rt (AP, AFP)