You can watch Mayor Cranley's full apology in the video player above.

CINCINNATI -- Mayor John Cranley apologized to the Fraternal Order of Police Thursday night after his office issued a proclamation honoring the man who ambushed and killed Cincinnati Police Officer Sonny Kim.

"This was a huge mistake," Cranley said, pausing to wipe tears from his eyes. "At the end of the day, the buck stops with me and there is no excuse. I am sorry, and it won't happen again."

Officer Sonny Kim, who died June 19, 2015.

According to a retraction issued by the city, a new employee at Cranley's office was the one who stamped the proclamation that June 1, 2017, would become "Tre Day" in honor of Trepierre Hummons. The proclamation depicted Hummons as a person whose life "will be a life remembered through the Trepierre Foundation's efforts to impact mental illness in kids and young adults."

That's not how Cincinnati police officers remember him.

Here's a copy of the letter from Mayor Cranley to FOP president. @WCPO pic.twitter.com/5429QV6sYo — Ashley Zilka (@ashleyzilka) May 18, 2017

Hummons, 21, died June 19, 2015 after calling police to report a suspicious, armed individual in his neighborhood. When Officer Kim arrived at the scene, police said Hummons shot him and wrestled his service weapon away; he then fired at other responding officers before being shot himself. Former Cincinnati Police Chief Jeffrey Blackwell referred to the incident as a "suicide by cop."

Both Hummons and Officer Kim died of their wounds at the University of Cincinnati Medical Center.

Copy of retraction of proclamation sent to Ronald Hummons, father of TrePierre Hummons @WCPO pic.twitter.com/iX1s8TrwT4 — Ashley Zilka (@ashleyzilka) May 18, 2017

The request for a commemorative "Tre Day" had been made by Hummons' father, who did not mention his child's last name or the incident with Kim when he made the request, and granted by communications director Holly Smith without the mayor's knowledge or approval, Cranley said.

"This was completely and utterly my fault and I apologize to anyone it has hurt," Smith said in a Skype call with WCPO. "Truly I do."

Bobbi Dillon, Cranley's chief of staff, wrote in a retraction letter to Hummons' father that "Mayor Cranley will not issue a proclamation that honors the man who murdered Cincinnati Police Officer Sonny Kim."

Cranley also sent a statement to Cincinnati Fraternal Order of Police President Dan Hils.

"Sonny Kim is a hero and as long as I am Mayor, Cincinnati will not honor in any way the man who murdered him in cold blood," Cranley wrote. “I have personally called Sonny Kim’s wife, Jessica, to apologize for this error.

"I cannot express how deeply sorry I am that this has happened,” Cranley continued. “Cincinnati has the world’s greatest police officers and police department. I am truly grateful for the work you do and the sacrifices you make every day for this city and I hope we can continue to work together to make Cincinnati a better place for all of us."

Hils said he was disappointed by the blunder, especially because it occurred during Police Memorial Week, but believed in Cranley's sincere commitment to the Cincinnati Police Department. He added that he was glad the mayor had taken responsibility for the faux pas.

"I believe real leaders do that even in the worse of times," he said. "The ones that run and hide are the ones that we should not have."

According to Hils, he'd heard from other police officers in his organization who were less disposed to forgiveness. He wouldn't ask them to let it go until they arrived at the decision themselves, he said, but he would be there to listen.

"They have the right to speak out," he said. "They are the ones that go out and do this job every night and take on the risks."

Cranley was scheduled to speak at a memorial event for fallen officers Friday. Hils said he would "pray on that" to decide whether or not it might still happen.