Philadelphia Mayor Michael Nutter is urging city police to use force only "if absolutely necessary" as the nation grapples with several officer-involved shootings.
Philadelphia police arriving for work for several days will be watching a video message from the mayor.
Nutter says the public is feeling "confused, dismayed, and angry" in the wake of the police-involved deaths in Ferguson, Missouri and New York City.
Two grand juries have voted not to charge any of the officers involved, sparking protests in Philadelphia and elsewhere.
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Nutter tells his officers that Americans aren't against policing, but instead fear "bad policing."
His police commissioner, Charles Ramsey, serves on President Barack Obama's new Task Force on 21st Century Policing.
The group hopes to find ways to boost public trust in the nation's police departments.