Police officers marching in an annual memorial to fallen officers Friday were heckled by activists angry over last month's fatal shooting of an unarmed black man by a white officer.

"We pay our policemen. They ought to be able to take care of all of us," Ras-Sudan Uhuru, 43, shouted at officers leaving for a one-mile procession to police headquarters.

About 20 activists held signs that said "No Racist Police" and "Stop Killing Us — Or Else." Several were arrested.

Rioting erupted after the April 7 shooting of Timothy Thomas, 19, the 15th black man killed in confrontations with Cincinnati police since 1995. More than 800 people were arrested and dozens were injured in the city's worst racial unrest since 1968.

The 27-year-old officer was later charged with two misdemeanors.

At a ceremony before the march, Police Chief Thomas Streicher called the officers "human beings who sometimes make mistakes."

"They have an extraordinary commitment to their society and extraordinary commitment to duty," he said.