Hours after Portland police unleashed tear gas on protesters in portions rarely seen even in this fractious city, Mayor Ted Wheeler directed the police chief to reduce the use of chemicals. But he stopped short of a blanket pause on tear gas—instead saying officers should only use it if their personal safety was endangered.

"Today, I directed Portland Police Chief Jami Resch that gas should not be used unless there is a serious and immediate threat to life safety, and there is no other viable alternative for dispersal," Wheeler said in a statement. "I strongly believe that gas should not be used to disperse crowds of nonviolent protesters or for general crowd management purposes. It should only be used in response to violence that threatens life safety."

On Friday evening, Wheeler told protesters of police violence that he was working on new restrictions on the use of tear gas.

Within hours, some protesters tested that commitment, knocking over a fence outside the Multnomah County Justice Center—and police used gas like they needed to exhaust their supply.

Riot police repeatedly tossed canisters of gas into groups of protesters for several hours. Demonstrators flung it back at the cops. Officers used gas to drive crowds away from the Justice Center, sometimes chucking it directly into the center of crowds. People ran frantically along the downtown Transit Mall, choking and retching.

Police said officers deployed tear gas and explosive devices—apparently stun grenades—because protesters were throwing bottles, bricks and cans full of White Claw and beans at officers. They also said they were concerned for the safety of inmates housed inside the Justice Center, which rioters set on fire one week previously.

Video by freelance journalist Sergio Olmos shows protesters came ready for gas. As in Seattle, they carried umbrellas, which they used to form a phalanx in the streets. Others brought leaf blowers to clear the chemicals.

The new images of chemicals and chaos came hours after a black activist group, Don't Shoot Portland, sued the city in federal court to halt the use of tear gas and other chemicals. Two city commissioners, Jo Ann Hardesty and Chloe Eudaly, have decried the use of chemical irritants during the COVID-19 pandemic, warning that coughing and choking will only further spread the virus.

It was not immediately clear whether Wheeler's directive today would bar officers from using gas in the manner they did last night. The Police Bureau issued statements on social media late Friday night saying officers were in physical danger from protesters hurling rocks and the broken necks of glass bottles.