FILE PHOTO: Former U.S. Vice President Joe Biden accepts the 2020 Democratic presidential nomination during a speech delivered for the largely virtual 2020 Democratic National Convention from the Chase Center in Wilmington, Delaware, U.S., August 20, 2020. REUTERS/Kevin Lamarque/File Photo
Democratic presidential nominee Joe Biden on Sunday called violence at protests in Portland, Oregon, unacceptable and challenged President Donald Trump to stop “recklessly encouraging” it, after one person was killed during clashes between rival groups.