PORTLAND, Ore. - Portland, Oregon's independent police oversight body has opened investigations into over 40 complaints related to protest policing.

The Independent Police Review's quarterly report offers the first look at the growing number of complaints against Portland police at nightly protests since the killing of George Floyd in police custody, The Oregonian/OregonLive reported.

The city's complaint process is the public's tool to hold police accountable for specific actions.

Most of the Independent Police Review investigations are related to allegations of unnecessary force by police at the protests, director Ross Caldwell said. The office also has some open complaints about the general conduct of officers interacting with Portlanders at protests.

The protests against police brutality and systemic racism began in Portland in late May. The demonstrations have routinely drawn hundreds, and sometimes thousands of people.

The protests quickly became a flashpoint between police and protesters. Some protesters scrawled graffiti, broke windows and threw things at officers on May 29. The night culminated in forceful dispersals by police after some protesters looted luxury stores and a Target, and lit a fire in an office at the downtown Justice Center. The city responded with several days of curfews and much-criticized tactics of hitting Portlanders with batons and deploying tear gas, pepper spray, stun grenades, impact munitions and an ear-splitting warning sound.

Police have continued to use force since the early days of protest, as have protesters continued to tag buildings with graffiti and throw various objects at officers, including water bottles, eggs and fireworks.

Federal judges have banned or limited use of many of the tactics unless police say they believe life or public safety are at risk. Police have more recently used batons and lines of officers to push people back at protests and occasionally, used tear gas and munitions after declaring civil disturbances.

Portland's Citizen Review Committee, an advisory body to Portland police and the Independent Police Review have condemned the police tactics.

The Independent Police Review investigations are a fraction of the thousands of complaints filed since the protests began. Many were form letters listing demands the Independent Police Review has no power to enact, like abolishing the Portland Police Bureau, Caldwell said.