Minneapolis police officers will face restrictions on entering a person's home unannounced under a new policy banning most "no-knock" search warrants, the latest attempt by city leaders to reform police practices in the wake of George Floyd's killing.

The change would, for the first time, establish clear expectations for MPD officers before crossing the threshold of a home. Surprise police raids have resulted in the deaths of innocent civilians and most recently came under harsh criticism after police in Louisville, Ky., fatally shot Breonna Taylor in her home last March.

Mayor Jacob Frey called the move "overdue."

"This is really about proactive policymaking, and we can't prevent every tragedy, but we can limit the likelihood of tragedies occurring and then set a clear, objective standard for both the police and the community," he said in an interview late last week.

Starting Monday, officers must identify themselves as "police" and announce their purpose as "search warrant" before entering any domicile — regardless of whether a judge signed off on an "unannounced" or "no-knock" entry. Once inside, officers are instructed to periodically repeat those announcements in case occupants didn't hear them. The same rules, which mirror those already in place across the river in St. Paul, also apply for arrest warrants.

The practice, most often used by SWAT officers, should help maintain the element of surprise and preservation of evidence while eliminating confusion about who's entering the building, said police spokesman John Elder.

Under new guidelines, no-knock warrants would be acceptable only in high-risk circumstances such as a hostage situation, when "giving an announcement would create an imminent threat of physical harm to victims, officers or the public."

If investigators want an exception to search a residence without warning, they will need express permission from the chief or a designee.

MPD executed an average 139 no-knock warrants a year.

"Even amid the most difficult circumstances, our men and women of the Minneapolis Police Department continue to carry out their duties with the highest level of excellence," Chief Medaria Arradondo said in a statement. "By implementing this new policy, we're committing ourselves to continued improvement and ensuring best practices are cemented in policy within this department."

The policy change comes six months to the day after Floyd's death at a south Minneapolis street corner, which sparked a wave of protests and national reckoning on racial justice. Floyd died May 25 after since-fired officer Derek Chauvin pressed his knee into Floyd's neck, ignoring his pleas for help until he fell unconscious and later died.

Since then, the department has banned the use of chokeholds and neck restraints, strengthened requirements to intervene in excessive-force cases, limited the number of people who can authorize the use of crowd-control weapons and allowed for wider body-camera reviews, under an agreement with the Minnesota Department of Human Rights.

Frey's office also made other changes, such as requiring officers to document attempts to de-escalate situations and restricting access to body camera footage before officers file their reports.

The latest revision puts Minneapolis more in line with cities including Louisville; Houston; Memphis; Indianapolis and Aurora, Colo., as well as the states of Oregon, Florida and Virginia.

The American Civil Liberties Union urged law enforcement agencies to ban no-knock warrants following the death of 26-year-old Taylor, who was shot eight times by police on March 13 after three narcotics officers used a no-knock warrant to bust down the door of her apartment during a late-night drug investigation.

Her boyfriend mistook the raid for a home invasion and fired back, striking a detective. Police were looking for Taylor's ex, who was already in custody. No drugs were found.

That case exemplifies why no-knock warrants are so dangerous, said Hennepin County Chief Public Defender Mary Moriarty.

"If you're in your home and you have no idea who's actually breaking into your house, you are going to react — and you might react the way Breonna Taylor's partner did with a gun," she said. "It's not safe for officers or residents."

However, Moriarty lauded MPD's new policy as a "terrific step forward" in reducing the number of such encounters.

A 2014 ACLU report on police militarization detailed several botched SWAT team raids that killed innocent people as no-knock warrants were served, including one that year in Atlanta where an errant flashbang grenade caused a toddler to be put into a medically induced coma.

In Minneapolis' most high-profile case, a flashbang grenade thrown by SWAT members during a 1989 raid inside a north Minneapolis apartment started a fire, killing an older Black couple.

Police officials apologized, calling Lloyd Smalley, 71, and Lillian Weiss, 65, accidental victims of the war on drugs.

The officers were cleared of any criminal wrongdoing.

Then, in 2007, MPD officers executing a no-knock search on the wrong house exchanged gunfire with Vang Khang, who thought they were burglars. His wife and six children, ages 3 to 15, were in the house. Police blamed the mix-up on bad intel from an informant.

The Associated Press contributed to this report.

Liz Sawyer • 612-673-4648

Liz Navratil • 612-673-4994