PHOENIX — The American Civil Liberties Union of Arizona says Phoenix police failed to warn protesters before using chemical irritants after a presidential rally five months ago.

Police officers used pepper spray to break up the crowd on Aug. 22 after they say people tossed rocks and bottles and dispersed gas on downtown streets.

Four people were arrested.

Phoenix police released a 30-page “after-action report” Monday on President Donald Trump’s visit.

Chief Jeri Williams says her department had only six days’ notice for planning and security compared to 18 months of preparation for a Super Bowl.

The ACLU says Phoenix police lacks an adequate system for tracking the use of less-lethal weapons.

The organization filed a lawsuit in November after police officials were slow to release public records concerning the August incident.