Buffalo Bills coach Sean McDermott was on the defensive Thursday after it emerged that he used the Sept. 11, 2001, terrorist attacks as an example of good teamwork in a speech to his players.

In an attempt to emphasize the importance of togetherness, he cited the 9/11 hijackers — who killed almost 3,000 people in the deadliest terrorist attack on U.S. soil — as an occasion where everyone was “on the same page.”

The remarks were made during a team meeting four years ago, but were not reported until Thursday. A somber McDermott addressed them in an unscheduled news conference.

“My intent in that meeting that day was to discuss the importance of communication and being on the same page with the team. I regretted mentioning 9/11 in my message that day, and I immediately apologized to the team,” McDermott told reporters.

“Not only was 9/11 a horrific event in our country’s history, but a day that I lost a good family friend,” he added.

The comments emerged in a series of longform articles on the Bills from journalist Tyler Dunne, who runs Go Long, an online paid-for football publication. Dunne cited conversations with 25 unnamed sources within the franchise with firsthand knowledge of the speeches. NBC News can’t verify the exact language McDermott used.

Dunne wrote that McDermott is known for giving lengthy and often unusual team talks. One morning at St. John Fisher College in Pittsford, New York, McDermott began telling the team about the importance of sticking together.

“But then, sources on hand say, he used a strange model: the terrorists on Sept. 11, 2001. He cited the hijackers as a group of people who were all able to get on the same page to orchestrate attacks to perfection. One by one, McDermott started asking specific players in the room questions,” Dunne wrote.

Dunne’s article continued:

McDermott did not dispute the account of his comments that day.

He said that he first became aware of the report through the team’s vice president of communication, Derek Boyko, and felt it necessary to address the subject right away. “When Derek shared this particular piece, I said, ‘Stop right there because this is important to me,’” McDermott said.

Following questions from reporters at the news conference, the coach said he was attempting the underline “the importance of communication, and being on the same page as a team.”

McDermott said that one player at the 2019 meeting had said his point had not been made clearly enough, which prompted him to speak to the team again an hour later.

“I brought everybody together and said this was the goal, this was the intent, and I apologize if anyone whatsoever felt a certain type of way coming out of that meeting,” McDermott said.

“If anyone misinterpreted or didn’t understand my message, I apologize. I didn’t do a good enough job of communicating clearly the intent of my message. That was about the importance of communication and that everyone needs to be on the same page, ironically enough. So that was important to me then and still is now,” he said.

McDermott added that he would be addressing the team about the speech again Thursday.

“As I mentioned to the team then that I regretted and apologized for me not doing a good enough job of communicating my point, I’m going to do the same with the team today,” he added. “So if there’s anyone new, they understand how important that is to me and my family because it’s an important event, a horrific event in our history.”

On the field, the Bills are 6-6 after an underwhelming season so far, leaving them second in the AFC East and needing to beat the Kansas City Chiefs on Sunday to boost their slim chances of making the playoffs.

Since McDermott was hired in 2017, the Bills have developed from also-rans into perennial contenders behind star quarterback Josh Allen. But they have failed to make it to the Super Bowl and this season’s struggles have fueled questions about McDermott’s job