Anti-Trump Protests Sweep the Nation for a Second Night, Trump Calls Them 'Unfair' Portland police described that city's protests as a "riot."

 -- Thousands of demonstrators took to the streets of several cities nationwide Thursday in a second night of rallies protesting the election of Donald Trump. While the gatherings were mostly peaceful, late-night vandalism and graffiti turned a march in Portland, Oregon, into what police described as a “riot.”

"Due to extensive criminal and dangerous behavior, protest is now considered a riot. Crowd has been advised," tweeted the Portland Police Department, who pointed the finger at "anarchists."

Thousands turned up in Portland's Pioneer Courthouse Square early in the night for a peaceful protest and march but, as the night wore on, individuals were seen vandalizing businesses and property in the city's Pearl District and throwing objects at police.

Police reported a total of 26 arrests for the night after they deployed rubber bullets and flash grenades to clear the streets.

At one point, a crowd of people stepped in to stop a bat-wielding man from smashing a transformer.

Individuals were also caught on camera smashing car windows with baseball bats.

A driver on the Hawthorne Bridge apparently threw laundry detergent at some of the protesters, who then took her keys and threw them over the overpass, according to ABC Portland affiliate KATU-TV.

Her car was abandoned on the bridge.

The community group Don’t Shoot PDX has organized the protests over the past couple nights. A spokesman for the group, Gregory McKelvey, told KATU they do not condone violence or vandalism and plan to lead with an "example of peace."

As protests kicked off across the country Thursday night, Trump took issue with the protests, tweeting, "Just had a very open and successful presidential election. Now professional protesters, incited by the media, are protesting. Very unfair!"

At about 6:14 a.m., the president-elect followed up with a more upbeat message on the night's unrest.

NEW YORK

Trump Tower, where the president-elect's offices are, was the site of demonstrations again.

Hundreds of angry protesters descended upon the midtown Manhattan skyscraper carrying signs that read "Not My President" and "Divided States of America."

DALLAS

At a protest march in downtown Dallas, at least three people were arrested, according to police.

The Next Generation Action Network organized the rally, which started at AT&T Victory Park Plaza and made its way through the streets of downtown back to the plaza.

"As we wrap our minds around this failed attempt at democracy that we as a country have witnessed in this election, and brace ourselves as Americans for a new Republican commander-in-chief with a majority Republican House and Senate; we are even more strengthened in our resolve to fight," a statement from the Next Generation Action Network read before the protest. "Most everything out of the Trump campaign has been divisive and contrary to those values written in the U.S. Constitution."

Elsewhere in Texas, at least two protesters were arrested, one for shoving an officer, at an Austin protest, according to ABC Austin affiliate KVUE-TV.

About 100 people marched around Houston, with police reporting at least five arrests.

In the nation's capital, protesters gathered outside the newly opened Trump International Hotel around 6:30 p.m. They chanted and held signs that read "Not Our President" and "Trump is a racist."

"People are out here because of the principle of love and the principle of compassion and we are sincerely worried that that is dying," protester Nnamdi Akoli told ABC Washington affiliate WJLA-TV.

THE BAY AREA (SAN FRANCISCO, OAKLAND, BERKELEY)

The San Francisco Bay area was also a hotbed of protests Thursday.

Protesters returned to Oakland to protest the president-elect, descending upon City Hall carrying signs that read "Liberation, Not Deportation."

The demonstrators shut down Interstate 580, creating major traffic disruptions. Police reported at least six arrests.

Oakland police reported at least 11 arrests, and one individual who was detained with a cache of Molotov cocktails. The police department said it made arrests and issued citations for crimes including assault on officers, vandalism, failure to disperse, and public intoxication.

Earlier in the day, protests took place at high schools in Berkeley and Oakland, ABC station KGO-TV reported. About 1,500 Berkeley High School students staged a walkout around 8:20 a.m. and marched to the University of California at Berkeley, where a much larger demonstration was taking place. Some school staff members accompanied the students on the march to make sure they were safe. The crowd gathered peacefully at UC Berkeley as police officers looked on.

PHILADELPHIA

About 500 protesters gathered at the Municipal Services Building Thursday night for a vigil organized by GOP Hands Off Me, a multiracial feminist coalition.

"We're actually just creating the space for people to come together and say, 'This isn't our America, this isn't what we thought it was,' " Emma Boorboor of GOP Hands Off Me told ABC Philadelphia station WPVI-TV. "We're going to give ourselves the space to mourn essentially that this is what happened in America."

LOS ANGELES

Hundreds of marchers walked through the city's streets. The crowd started at a modest size of 50 to 75 rallying at Los Angeles City Hall, ABC Los Angeles station KABC-TV reported. They then started marching through the streets of downtown as one group merged with another and the crowd grew to several hundred. At least one demonstrator was arrested during the protest.

BALTIMORE

An estimated 600 protesters marched through the downtown area of the city. While the majority of the demonstrators were peaceful, some people blocked roadways and sat in the streets. Police detained two individuals during the protest. No charges have been filed at this time, according to a statement on the Baltimore Police's Facebook page.

MILWAUKEE

A scuffle broke out between Trump supporters and protesters at Milwaukee's Red Arrow Park, ABC Milwaukee affiliate WISN-TV reported. The scuffle was quickly broken up and there was no immediate word about any injuries. The incident followed a two-hour demonstration with hundreds of protesters that started at the park before moving to the streets.

“As of now, there have been no major incidents or arrests," the Milwaukee Police Department tweeted at about 8:30 p.m. local time.

ABC News' Rex Sakamoto, Julia Jacobo and Jonah Lustig contributed to this report.