DETROIT — The Detroit police department won key support Thursday for its use of facial recognition technology amid vocal concerns about privacy violations and false identifications.

After months of heated protests, the Board of Police Commissioners, a civilian body that oversees the Detroit police, approved new guidelines on Thursday that endorse the use of the technology along with safeguards to prevent its misuse. The new policy approved by the board restricts police use of facial recognition to still photographs connected to violent crime and home invasion investigations. The new guidelines also require several layers of approvals within the department before the technology can be used and prohibit certain uses, such as identifying people at political events like protests.

“This is a great day,” said police Chief James Craig, noting that when the technology is used to identify criminals, “we all win. Families win. The city wins.”

Critics, though, said the vote would jeopardize the civil liberties of Detroiters.

“You voted yes on some high-tech racism that’s being used by the Detroit Police Department in this city,” said Reggie Crawford, a Detroiter who identified himself as a former police officer and a former member of the oversight board when he addressed the board after the vote. “This technology is flawed.”

Software that compares people’s photos to images in a database to try to learn their identities has been the subject of heated opposition across the country, especially given research showing the tools are more likely to misidentify people with darker skin.

The debate has been especially emotional in Detroit, where about 80 percent of residents are black, a larger share than in any other big city in the country. And while some cities, including Oakland and San Francisco, have voted preemptively to ban their police departments from using the technology, Detroit began using it more than two years ago without first seeking guidance from a police oversight board.

Craig proposed new guidelines to the board last spring after debate over police use of facial recognition technology became a national issue. In the face of strong criticism, he offered subsequent amendments, notably barring the use of the technology on live video streams such as those that flow to Detroit's police headquarters from hundreds of gas stations, restaurants and other businesses around the city that participate in a police surveillance program called Project Green Light.

“I took the community's concerns to heart,” Craig said. “We want to reassure everyone: This is about supporting victims, family members of victims, identifying violent predatory criminals.”

Craig says the technology has already been used in Detroit to identify suspects in numerous violent crimes. He said trained police analysts use a multi-step process to prevent misidentifications from the technology.

But civil liberties advocates and community groups were furious to learn the tool had been in use without a full public review. They’ve called on the Board of Police Commissioners to support a ban of the practice.

The board heard months of emotional testimony from citizens calling for a ban, and an agenda for Thursday’s meeting posted on the board’s website in advance showed the body initially intended to hear more public comments before voting. Instead, a board member made a motion to move the vote up, before public comment. The board then voted 8-3 without discussion to support the new guidelines. Later, a board member said the original agenda was written in error.

One board member, Evette Griffie, said she voted in support of the technology because “it’s going to free up officers who are doing detective work,” adding, “they’ll spend less time chasing criminals and trying to find out whodunit and can go patrol the streets.”

Others said they endorsed the technology after amendments were added to the new oversight policy, including rules that would create disciplinary consequences for police personnel who misuse the technology.

Griffie said she initially had concerns about possible misidentification of suspects but noted that facial recognition matches cannot be used against defendants in court. “It’s a tool,” she said. “It provides a lead.”

The question of the Detroit police’s use of facial recognition technology will now shift to the City Council and the Michigan legislature, where bills are in the works that could ban the technology, though it’s yet clear whether they’ll draw wide support.