(CBS NEWS) --  United Airlines (UAL) will likely face a lawsuit from David Dao, the doctor who was violently dragged off an overbooked flight on Sunday, Dao’s attorneys said in a wide-ranging press conference in Chicago Thursday. 

“Will there be a lawsuit? Probably,” said Thomas Demetrio, one of the two aviation lawyers representing Dao. He hinted there could be multiple defendants, saying “just because United is responsible, doesn’t mean the city of Chicago isn’t responsible.” 

Video of Dao’s violent removal went viral, sparking widespread criticism of the airline and its CEO’s apparently tone-deaf attempts to explain himself.  

Demetrio said that the experience of being dragged off the plane was more traumatizing for Dao than fleeing Vietnam in 1975. He said his client suffered a severe concussion and a broken nose, and lost two front teeth. Dao spent several days in the hospital after the April 9 incident, and was released late Wednesday night, according to his lawyers.

The legal team offered few details on the timing or details of the likely suit, noting that it would likely come “much sooner” than the legal window of two years after an incident. 

Demetrios played down the possibility of a class-action suit, saying he believes what happened to Dao was exceptional. “Rudeness and bullying of customers has gone the next step now to injury,” he said. 

Demetrio also said that he hadn’t heard from the company’s CEO, but United countered that claim in a statement shortly after the press conference. 

In the statement, United apologized to Dao and detailed changes it was making, including no longer using law enforcement officers to take passengers off a flight and reviewing policies and training programs. 

“We continue to express our sincerest apology to Dr. Dao.  We cannot stress enough that we remain steadfast in our commitment to make this right,” the statement said, in part. “This horrible situation has provided a harsh learning experience from which we will take immediate, concrete action. We have committed to our customers and our employees that we are going to fix what’s broken so this never happens again."

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