CHICAGO — Facing public outrage over forcibly dragging a man off a plane, United Airlines on Wednesday promised that this kind of incidents would never happen again.

"This will never happen again on United Airlines," CEO of United Airlines Oscar Munoz told ABC news in an interview. "We are not going to put a law enforcement official onto a plane to take them off..to remove a booked, paid, seated passenger."

The promise came three days after a passenger was brutally removed from one of its flights to make room for its own employees. In the process, the passenger's mouth was hit and bled.

The video of this bloody incident went viral on internet and sparked social media uproar, in which many are echoing calls to boycott United Airlines.

The initial response from the top executive drew him even more criticism. In a letter to employees that was leaked to CNBC Monday, Munoz described the passenger as "disruptive and belligerent."

During his interview on Wednesday, Munoz expressed regret for his earlier comments, saying he did not blame the passenger and that his initial words "fell short" of what he felt.

The CEO also pledged a full investigation into the matter and suggested possible change to the way local law enforcement deals with passengers aboard the airlines.