ST. LOUIS • A federal judge heard testimony from three people who complained of excessive police tactics — including indiscriminate use of tear gas — and then provided limited relief Thursday in a temporary restraining order.

U.S. District Judge Carol Jackson’s order requires police to warn crowds of impending use of tear gas and provide “reasonable” time for people to disperse first. But she did not define what is reasonable, saying that would be at police discretion.

She rejected a request for an order that tear gas be used only as a “last resort,” saying there was no way to gauge that circumstance.

Jackson showed sympathy for some of the complaints, for example a failure to distinguish among targets of enforcement action. “There was no distinction drawn in the way peaceful protesters were treated and the way criminals were treated, even though the police do make those distinctions in other situations,” she said.

She also said, “People involved in peaceful, nonviolent political speech can do that without being lumped in with the criminals.”