THIRTEEN people were arrested and six were injured, as over 1,200 right-wing demonstrators and counterprotesters descended on downtown Portland on Saturday, U.S. police said.

Portland Police Lt. Tina Jones said there had been at least 13 arrests. In addition, officers confiscated a number of weapons, including knives, shields and stun guns.

Portland Mayor Ted Wheeler said that he was pleased that police were able to keep the city safe while also helping to “protect the core American value of free speech.”

Jessyca Jones, a counterprotester who was on the streets Saturday, told ABC News the environment was “tense” and that there had been “lots of fights.”

At around 4:30 p.m. local time, the Portland Police tweeted, “Police are having plastic water bottles thrown at them as they are making an arrest on SW Yamhill and Park.”

After that, police began advising people to clear the streets or face arrest.

“Police are advising this is now a civil disturbance. Crowd needs to leave the area and go northbound on park or any direction eastbound. This means everyone,” Portland Police tweeted.

The city has been bracing for several militant right-wing groups to arrive in the city, along with scores of counter-protesters.  (SD-Agencies)