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.

More: Judge Orders St. Louis Area Police to Give Protesters Tear Gas Warning and Time to Flee : News