Ohio police officers who were in Milwaukee to help with security at the Republican National Convention shot and killed a man Tuesday who local authorities said had knives in both hands and was trying to attack another man – an encounter that prompted calls for transparency from local activists.

Milwaukee Police Chief Jeffrey Norman told reporters the officers from Columbus, Ohio, saw a man with two knives involved in an altercation with an unarmed man and went to intervene.

The suspect refused commands to drop the knives and charged the other man, the chief said, and five officers opened fire, killing the assailant.

“Someone’s life was in danger,” Norman said at the news conference. “These officers, who are not from this area, took (it) upon themselves to act to save someone’s life today.”

Two knives were recovered at the scene, Norman said. Authorities believe the initial altercation was not related to the convention.

Columbus Division of Police Chief Elaine Bryant said in a statement the shooting happened on the convention’s outer security perimeter, within the zone to which their officers were assigned.

The chief also released video from the body-worn camera of one officer involved in the shooting.

The 31-second video, which begins partially blurred, starts with the officers engaged in a briefing before turning their attention to an altercation involving two men nearby.

“He’s got a knife. Yes he does,” one officer says in the video.

They immediately draw their weapons and run toward the altercation, yelling at the armed man, “Drop the knife!” the video shows.

As the officers come near, one man holding something in each hand appears to move toward the other man, the video shows. The officers then shoot at the moving man, and he falls to the ground, the video shows.

Milwaukee Mayor Cavalier Johnson said the shooting was a tragedy that appears to be justified.

“Any officer in that same situation where they witness somebody who’s going to cause death or serious bodily harm to somebody with a gun or, in this case, with a knife – not just one knife, but two knives – would have taken the exact same action to preserve life,” Johnson told CNN’s Ryan Young.

The force from Columbus is in Milwaukee to assist with security for the Republican National Convention, but Johnson said the incident had no connection to the convention.

Johnson, a Democrat who has endorsed President Joe Biden for the upcoming election, said former President Donald Trump called him Tuesday to express appreciation for the city’s public safety efforts hosting the convention.

Milwaukee activists call for accountability

The shooting in Milwaukee comes more than a year after the US Department of Justice released recommendations for reform of the Columbus Division of Police following a nearly two-year review of its policies. The division requested the review after facing multiple controversies, including criticism over its management of racial justice protests in 2020 and deadly police shootings, including those of Andre Hill and Ma’Khia Bryant.

The recommendations were aimed at strengthening the police department’s relationship with the community and included longer training periods for officers and technology improvements.

The fatal shooting sparked anger and criticism by local activists.

At an evening news conference held by people calling for police accountability, activist Alan Chavoya said, “We’re not even two days into this RNC and we have a casualty. How is that possible? And guess what, as always, no answers from the MPD. No transparency, no accountability.”

“We want answers, we want to know why was there an out-of-state police officer in this area in the first place,” Pastor Radontae Ashford of the Infinite Church said at the news conference. “There’s only two reasons … that any of us that even live in Milwaukee would even be in this area, either for something helpful or something harmful.”

In a statement, the American Civil Liberties Union of Wisconsin called for a “full and transparent” investigation into what led up to the shooting.

“More than 4,000 additional law enforcement officials are in Milwaukee for the RNC, and we’ve long feared how this heavy police presence could increase the risk of deadly police encounters, especially by out-of-state officers who don’t know and aren’t accountable to our community,” the statement from Executive Director Melinda Brennan read. “We offer our condolences to the friends and family of the person killed.”

CNN’s Andy Rose contributed to this story.