The Chicago Department of Aviation is defending the officers in the infamous United Airlines video, saying they used “minimal but necessary force” when they dragged a passenger off a flight.

A report from the department describes what the officers say happened earlier this month on United Express Flight 3411. It says that the passenger, David Dao, was “aggressive” and “violently” swung his arms at officers, who then had to forcibly remove him from the plane.

The encounter, captured on videos taken by other passengers, and the airline company’s handling of the aftermath set off an international outrage and a prolonged public relations nightmare for United.

According to the report, flight crews called security officers because a passenger, Dao, was yelling and refusing to leave the aircraft. A United official earlier told passengers that it needed four volunteers to give up their seats for off-duty crew members. But no one volunteered, so the airline chose the passengers. Three agreed to leave, but Dao, a 69-year-old Kentucky resident, refused.

Three officers tried several times to convince Dao to give up his seat, the report says.

“I’m not leaving this flight that I paid money for. I don’t care if I get arrested,” he told one of the officers, according to the report.

The report says Dao became increasingly combative and began swinging his arms with his fists closed after one of the officers tried to grab him. It says the officer was able to pull Dao up from his seat and toward the aisle, but then lost his grip because Dao kept fighting.

That’s when Dao fell and hit his mouth on the armrest, according to the report, which was posted online by the Chicago Tribune.

At some point, Dao went limp. Disturbing videos taken by other passengers show him bleeding from the mouth as he was dragged off the plane.

The report says Dao was taken to the jet bridge, where he lay down and told the officers that he’s diabetic. At some point, it said, he ran back to the aircraft, held onto to a pole inside and said, “I’m not getting off the plane. Just kill me. I want to go home.”

Dao was again removed from the plane and eventually agreed to be taken to a hospital.

The incident happened April 9 at Chicago O’Hare International Airport, on a plane that was headed to Louisville. The officers involved have been placed on leave.

Outrage over the incident was compounded by the airline company’s initially muted response to it. United’s chief executive, Oscar Munoz, released a statement the following day apologizing for “having to re-accommodate” the passengers. In a letter he sent to his employees, Munoz appeared to blame Dao, saying he “refused” to cooperate after he was “politely asked” to leave, prompting flight crews to call for help.

Two days after the incident, Munoz issued a more humbled apology, saying he was “disturbed” by what happened and that he “deeply” apologizes to Dao. By then, United’s stock prices had plummeted and outrage had reached China, where public anger was fueled by reports that Dao is Asian. He is originally from Vietnam.

United has since changed its policies so that crew members will no longer be allowed to displace passengers who are already seated on the plane. Off-duty airline crews are now required to check in at least an hour before a flight leaves. The purpose is to avoid having to find a seat for a crew member after all the passengers have already boarded.

United also will no longer ask law enforcement officers to remove passengers from flights “unless it is a matter of safety and security,” according to a statement.

Munoz, who was awarded “Communicator of the Year” by PRWeek just a month before the public relations debacle, also promised further review of the airline’s policies and to release a public report by Sunday.

But Munoz’s assurances have so far done little to convince lawmakers that broader changes aren’t necessary.

A group of Democratic senators said this week that United hasn’t responded to its questions about the incident.

“I am disappointed and troubled that United Airlines has so far failed to answer basic questions about the troubling incident aboard Flight 3411,” U.S. Sen. Maggie Hassan, D-New Hampshire, said. “No passenger should ever experience the mistreatment that we all saw on that United flight. I will continue to use all of the tools at my disposal, including introducing legislation later this week, to help prevent such an incident from happening again and to strengthen consumer protections for the flying public.”

Hassan, along with U.S. Sens. Brian Schatz, D-Hawaii, Dick Durbin, D-Illinois, and Charles E. Schumer, D-New York, sent a letter to Munoz demanding a more detailed account of what happened on the plane and a clearer understanding of the airline’s policy on removing ticketed passengers after they’ve boarded a flight. The senators have yet to receive a response.

United and the Chicago Department of Aviation also have not responded to a separate set of questions from leaders of the Senate Commerce Committee.

In a letter sent to leaders of the Senate’s Commerce, Science and Transportation Committee and the Subcommittee on Aviation Operations, Safety and Security, Munoz outlined concrete actions the airline has taken in light of the dragging incident. He said United will provide answers no later than Thursday.

Likewise, Ginger S. Evans, head of the Chicago Department of Aviation, which manages O’Hare, and the three officers involved in the incident, also had asked for more time to respond.

A few lawmakers have indicated plans to introduce legislation in response to the incident.

U.S. Rep. Neal Dunn, R-Florida, said last week that he plans to introduce a bill that would prohibit airlines from involuntarily removing paying passengers off a flight to make room for other passengers or crew members when there are no empty seats left.

“Passengers should have the peace of mind to know they will not be dragged off a plane once they’re in their seat,” Dunn said in a statement.

U.S. Sen. Richard Blumenthal, D-Connecticut, had sent a letter to Secretary of Transportation Elaine Chao demanding a “swift, sweeping investigation into United Airlines and the industry practices that led to this incident.”

Blumenthal said in an earlier statement that he’s working on a “passenger bill of rights.”

Dao, a doctor from Kentucky, suffered a serious concussion, a broken nose and other injuries. He also lost two of this teeth, according to his attorney, Thomas Demetrio.

Demetrio had said that his client will “probably” sue United.