The head of the nation's largest police organization formally apologized on Monday for "historical mistreatment" of racial minorities by police and called on officers to work with minority groups to improve trust.

The statement was notable in an era of nationwide protest and activism over police shootings and heightened fear among officers over violent retaliation against them.

Speaking in San Diego at the annual conference of the International Association of Chiefs of Police, Terrence Cunningham said that officers "cannot change the past" but "must change the future" when it comes to how they relate to minority groups.

In his short speech, which drew a standing ovation at the San Diego Convention Center, Cunningham avoided mentioning protests over recent police shootings in Charlotte, N.C., and elsewhere by name, and also did not mention targeted killings of police officers over the summer in Dallas and Baton Rouge, La.

Cunningham, the Wellesley, Mass., police chief, also did not mention the Black Lives Matter movement, which has gained traction nationwide with its criticisms of modern-day policing tactics and deadly shootings of black Americans.

Instead, he focused on apologizing for the "darker periods" when police carried out "many unpalatable tasks, such as ensuring legalized discrimination or even denying the basic rights of citizenship to many of our fellow Americans."

Cunningham said that history has led to mistrust today, and he called on police to work together with communities to build better relationships.

"While we obviously cannot change the past, it is clear that we must change the future. We must move forward together to build a shared understanding. We must forge a path that allows us to move beyond our history and identify common solutions to better protect our communities," he said.

Cunningham said today's officers are not responsible for actions of the past, a nod to officers who, for example, enforced segregation and Jim Crow laws.

"Those who denounce the police must also acknowledge that today's officers are not to blame for the injustices of the past," he said. "If either side in this debate fails to acknowledge these fundamental truths, we will be unlikely to move past them.

"Overcoming this historic mistrust requires that we must move forward together in an atmosphere of mutual respect. All members of our society must realize that we have a mutual obligation to work together to ensure fairness, dignity, security and justice.

"It is my hope that, by working together, we can break this historic cycle of mistrust and build a better and safer future for us all."