(Portland, OR) -- The Portland Police Bureau says it's investigating allegations that its officers injured people during Saturday's dueling protests downtown. Bureau Chief Danielle Outlaw issued a statement yesterday saying they take issues surrounding the use of force seriously. Outlaw added that they're investigating to see if force was used and, if so, if it was used within bureau policy and guidelines. The American Civil Liberties Union (ACLU) of Oregon yesterday criticized the Bureau's response to the protest, calling their actions "completely unacceptable in a free society." They added that the "repeated use of excessive force, and the targeting of demonstrators based on political beliefs are a danger to the First Amendment rights of all people." The Patriot Prayer and Proud Boy groups encountered hundreds of counter-protesters at Saturday's unpermitted rally.