Police officers kneel in solidarity with protesters in Portland, Oregon, U.S. May 31, 2020 in this still image obtained from social media video. Across the United States a number of police officers have taken a knee and joined marches to show solidarity with posters demanding justice for George Floyd, a black man who died after gasping for breath as a white Minneapolis police officer knelt on his neck. PAIGE BARETTA via REUTERS

A man shakes hands with police officers who kneel in solidarity with protesters in Portland, Oregon, U.S. May 31, 2020 in this still image obtained from social media video. Floyd's death has caused outrage across a nation that is politically and racially divided during a polarizing presidential campaign, reigniting protests that have flared repeatedly in recent years over police killings of black Americans. PAIGE BARETTA via REUTERS

A police officer kneels down in solidarity with protesters during a rally against the death in Minneapolis police custody of George Floyd, in Washington, D.C., U.S. May 31, 2020. Officers have joined protesters in the street calling for change, including Genesee County Sheriff Christopher Swanson who walked alongside protesters saying, "incidents such as this undermine the work that police officers do to work with communities and keep people safe." REUTERS/Jonathan Ernst

A single officer takes a knee in solidarity with protesters during nationwide unrest following the death in Minneapolis police custody of George Floyd, outside the Oklahoma City Police Department in Oklahoma City, Oklahoma, U.S., May 31, 2020. Protests and eruptions of violence have not let up despite the arrest on Friday (May 2) of former Minneapolis police officer, Derek Chauvin, 44. He has since been charged with third-degree murder. REUTERS/Nick Oxford

New York police officers kneel along with protesters after protesters said they asked them to do so, in this still frame obtained from social media video in Queens, New York, U.S. May 31, 2020. Across the United States a number of police officers have taken a knee and joined marches to show solidarity with posters demanding justice for George Floyd, a black man who died after gasping for breath as a white Minneapolis police officer knelt on his neck. ALEEIA ABRAHAM /via REUTERS

Police officers kneel in solidarity with protesters in Portland, Oregon, U.S. May 31, 2020 in this still image obtained from social media video. Across the United States a number of police officers have taken a knee and joined marches to show solidarity with posters demanding justice for George Floyd, a black man who died after gasping for breath as a white Minneapolis police officer knelt on his neck. PAIGE BARETTA via REUTERS