Protesters form a human chain in front of a north Minneapolis police precinct and around their encampment during a protest in response of Sunday's shooting death of Jamar Clark by police officers in Minneapolis, Minnesota, November 18, 2015. State officials on Wednesday identified the two Minneapolis police officers involved in the fatal shooting of an unarmed black man that has sparked protests and dozens of arrests. REUTERS/Craig Lassig

A protester carries a sign as police stand their ground in front of a north Minneapolis police precinct during a protest in response of Sunday's shooting death of Jamar Clark by police officers in Minneapolis, November 18, 2015. REUTERS/Craig Lassig

A protester argues with a police officer in front of a north Minneapolis police precinct during a protest in response of Sunday's shooting death of Jamar Clark by police officers in Minneapolis, November 18, 2015. REUTERS/Craig Lassig

A member of Black Lives Matter tries to keep protesters back from the police line in front of a north Minneapolis police precinct during a protest in response of Sunday's shooting death of Jamar Clark by police officers in Minneapolis, November 18, 2015. REUTERS/Craig Lassig

A makeshift memorial is seen at the location where Jamar Clark was allegedly shot by police early Sunday, in Minneapolis, November 16, 2015. REUTERS/Todd Melby

A protester videotapes the event during a protest in front of a north Minneapolis precinct in response of Sunday's shooting death of Jamar Clark by police officers in Minneapolis, November 18, 2015. REUTERS/Craig Lassig

A police officer talks with demonstrators in front of a north Minneapolis police precinct during a protest in response of Sunday's shooting death of Jamar Clark by police officers in Minneapolis, November 18, 2015. REUTERS/Craig Lassig

Protesters form a human chain in front of a north Minneapolis police precinct and around their encampment during a protest in response of Sunday's shooting death of Jamar Clark by police officers in Minneapolis, November 18, 2015. REUTERS/Craig Lassig

A police officer watches demonstrators in front of a north Minneapolis police precinct during a protest in response of Sunday's shooting death of Jamar Clark by police officers in Minneapolis, November 18, 2015. REUTERS/Craig Lassig

Police officers and demonstrators have a standoff in front of a north Minneapolis police precinct during a protest in response of Sunday's shooting death of Jamar Clark by police officers in Minneapolis, November 18, 2015. REUTERS/Craig Lassig

Police officers watch as a demonstrator holds a sign in front of a north Minneapolis police precinct during a protest in response of Sunday's shooting death of Jamar Clark by police officers in Minneapolis, November 18, 2015. REUTERS/Craig Lassig

A protester argues with a police officer in front of a north Minneapolis police precinct during a protest in response of Sunday's shooting death of Jamar Clark by police officers in Minneapolis, November 18, 2015. REUTERS/Craig Lassig

Police stand their ground in front of a north Minneapolis police precinct during a protest in response of Sunday's shooting death of Jamar Clark by police officers in Minneapolis, November 18, 2015. REUTERS/Craig Lassig

Protesters and police stand-off in front of a north Minneapolis police precinct during a protest in response of Sunday's shooting death of Jamar Clark by police officers in Minneapolis, November 18, 2015. REUTERS/Craig Lassig