ATLANTA (AP) — Activists plan to rally in downtown Atlanta in response to a grand jury's decision not to indict the police officer who fatally shot an unarmed 18-year-old in Ferguson, Missouri.

Organizers say the "Community Speakout" is set for 5 p.m. to 9 p.m. Tuesday at Underground Atlanta, a shopping area in the heart of the city.

Thousands of people demonstrated late Monday in several U.S. cities to protest the grand jury's decision not to indict Darren Wilson, a white police officer who killed Michael Brown, who is black, on Aug. 9.

Atlanta Mayor Kasim Reed said in a statement that he urges everyone taking part in demonstrations to do so peacefully. Reed added that law enforcement officers must "show proper restraint and respect every citizen's constitutional right to assemble."