CHICAGO (Reuters) - One of the police officers who forcibly removed a passenger from a United Airlines UAL.N flight said "minimal but necessary force" was used in the incident that became a public relations disaster for the carrier, according to a report released by the city.

Video recorded by other passengers showed David Dao, a 69-year-old doctor, being dragged down the aisle with blood on his face after refusing to give up his seat on a flight from Chicago to Louisville, Kentucky on April 9.

Dao suffered a concussion and a broken nose, lost two front teeth and is likely to sue the airline, according to his lawyer, Thomas Demetrio. Initially, United did not apologize to Dao and described him as “disruptive and belligerent.” Some social media users in the United States, Vietnam and China called for a boycott. The carrier has since apologized several times.

Demetrio called the aviation police’s version of events outlined in the report as “utter nonsense. Consider the source,” said the lawyer’s spokeswoman, Helen Lucaitis.

In the first published version of events from the three officers involved, aviation police officer Mauricio Rodriguez said Dao became combative after he and two other officers tried to persuade the doctor to leave the plane.

Rodriguez was the first officer to arrive on the scene. Dao told the officers, “I’m not leaving this flight that I paid money for. I don’t care if I get arrested,” according to the report, released by the city on Monday,

Officer James Long described how he arrived later and tried to pull Dao from his seat after further negotiations failed. At that point Dao “started swinging his arms up and down with a closed fist.”

Long said he lost control of Dao as he swung, causing Dao to fall and hit his mouth on an arm rest. Long then “assisted the subject by using minimal but necessary force” to get him off the aircraft, Rodriguez said.

Dao later ran back on the plane and held onto a pole, stating “Just kill me. I want to go home,” Rodriguez said. Dao was then persuaded to leave so his injuries could be treated, Rodriguez said.

Officer Steven Smith, the third officer involved, gave a similar description of the incident in the report.

All three officers remain on paid leave while the incident is investigated. Aviation department policy calls for its officers to not board planes to handle customer service issues, according to officials.

“Only force reasonably necessary to defend a human life, effect an arrest or control a person shall be used by Aviation Security personnel,” according to the aviation department’s use of force policy.

United said on Friday it had asked a U.S. Senate panel for an extra week to answer questions about the incident.

United Chief Executive Officer Oscar Munoz has said he was “personally committed to putting proof behind our promise” in the carrier’s commitment to reforms.