Oregon Police and National Guard forces hunted down hundreds of far-left protesters in central Portland on Wednesday night and made at least ten arrests.
This city in the northwest of the United States which has been the scene of demonstrations since the summer has been placed on heightened alert by the governor of Oregon, Kate Brown.
Ms Brown extended a state of emergency on presidential election night to prevent violent protests.
The Multnomah County Sheriff’s Office said the situation of “widespread violence” that prevailed legally amounted to a riot, following the arrest of a man suspected of throwing a Molotov cocktail.
He repeatedly warned that law enforcement could use ammunition and tear gas.
“The rally in downtown Portland is considered a riot situation. Leave the area immediately, ”the sheriff’s office announced on Twitter at around 8:30 p.m. local time (04:30 GMT).
An AFP journalist present at the scene saw two arrests during a clash.
38-year-old student Michael Ream was apprehended by police who handcuffed him. “It’s always the same,” he said, his face bloodied, lamenting “the horrible behavior of the police.”
Earlier, protesters took part in a peaceful rally in a park in central Portland, where an array of far-left or anti-capitalist groups offered lectures and music.
Portland, a very liberal city, has for months been the scene of protests denouncing cases of abuse of police force against African Americans in various parts of the United States.
During the evening’s incidents, police seized weapons including a loaded rifle, knife, hammers and fireworks used as projectiles, the sheriff’s office tweeted.
He said protesters threw bottles and other items at police officers and smashed store windows.