Police hurled tear gas and flash-bang grenades in response to rowdy protests in Portland, Oregon, as people around the country once again took to the streets denouncing Donald Trump's presidential election victory.

Portland police said Friday night on Twitter that the tear gas was used in response to “burning projectiles” thrown at officers. Hundreds of people marched through the city, disrupting traffic and spray-painting graffiti.

Authorities said vandalism and assault had taken place during the rally, which organisers had billed as peaceful earlier in the day.

In other parts of the country, spirited demonstrations on college campuses and peaceful marches along downtown streets have taken place since Wednesday.

Hundreds joined a Friday afternoon “love rally” in Washington Square Park in Manhattan.

Leslie Holmes, 65, a website developer from Wilton, Connecticut, took an hour-long train ride to the demonstration her first protest since the 1970s, when she hit the streets of San Francisco to oppose the Vietnam War.

She described herself as an armchair liberal but declared, “I'm not going to be armchair anymore.”

“I don't want to live in a country where my friends aren't included, and my friends are fearful, and my children are going to grow up in a world that's frightening, and my granddaughters can look forward to being excluded from jobs and politics and fulfilling their potential, so I'm here for them,” she said.

Evening marches disrupted traffic in Miami and Atlanta.

Trump supporter Nicolas Quirico was traveling from South Beach to Miami. His car was among hundreds stopped when protesters blocked Interstate 395.

“Trump will be our president. There is no way around that, and the sooner people grasp that, the better off we will be,” he said. “There is a difference between a peaceful protest and standing in a major highway backing up traffic for 5 miles. This is wrong.”

More than a thousand protesters took to the streets across California after night fell including downtown Los Angeles, where over 200 were arrested a night earlier.

In Bakersfield, where Trump is far more popular than in most of the state, some held signs reading “Anti-Trump, Pro-USA.”

Small protests also were held in Detroit; Minneapolis; Kansas City, Missouri; Olympia, Washington and Iowa City.

More than 200 people, carrying signs gathered on the steps of the Washington state Capitol. The group chanted “not my president” and “no Trump, no KKK, no fascist USA.”

In Tennessee, Vanderbilt University students sang civil rights songs and marched through campus across a Nashville street, temporarily blocking traffic. A protest also occurred in Minneapolis.

In Chicago, multiple groups planned protests through Saturday.

Nadia Gavino, 25, learned about the rallies on Twitter and protested Thursday evening. Gavino, whose father is from Peru and whose mother is of Mexican and Lithuanian heritage, said she took Trump's harshest statements about immigrants and Latinos personally.

“I obviously agree that he's racist, he's sexist, he's phobic, he's misogynistic. He's all these things you don't want in a leader,” she said.

Ashley Lynne Nagel, 27, said she joined a Thursday night demonstration in Denver.

“I have a leader I fear for the first time in my life,” said Nagel, a Bernie Sanders supporter who voted for Hillary Clinton.

“It's not that we're sore losers,” she said. “It's that we are genuinely upset, angry, terrified that a platform based off of racism, xenophobia and homophobia has become so powerful and now has complete control of our representation.”

Demonstrations also were planned Saturday in Las Vegas, Los Angeles and other areas.

Previous demonstrations drew thousands of people in New York and other large urban centres. The largely peaceful demonstrations were overshadowed by sporadic episodes of vandalism, violence and street-blocking.