US President Barack Obama believes in the right of Americans to protest the election of Donald Trump in a non-violent manner, but wants people to hear the message that "we're Americans and patriots" before Democrats and Republicans, the White House says.
"It's important for us to remember, a day or two after the election, that we're Democrats and Republicans, but we're Americans and patriots first," White House spokesman Josh Earnest told reporters on Thursday.
"And that's the message the president hopes that most people will hear."
Police put up security fences around US President-elect Donald Trump's new Washington hotel and a line of concrete blocks shielded New York's Trump Tower as students around the country staged a second day of protests over his election.
A day after thousands of people took to the streets in at least 10 US cities from Boston to Berkeley, California, chanting "not my president" and "no Trump", fresh protests were held in Texas to San Francisco.
A Trump campaign representative did not respond to requests for comment on the protests but Rudy Giuliani, the former New York City mayor and a high-profile Trump supporter, called the demonstrators "a bunch of spoiled cry-babies".
The protesters blasted Trump for campaign rhetoric critical of immigrants, Muslims and allegations of sexual abuse of women.
WATCH: SBS US Election Correspondent Sarah Abo reports from the protests in New York City
More than 20 people were arrested for blocking or attempting to block highways in Los Angeles and Richmond, Virginia, early Thursday morning.
In San Francisco, more than 1000 students walked out of classes on Thursday morning and marched through the city's financial district carrying rainbow flags representing the lesbian, gay, bisexual and transgender communities, Mexican flags and signs decrying the president-elect.
Several hundred students at Texas State University in San Marcos took to the campus to protest Trump's election, with many students saying they fear he will infringe the civil rights of minorities and the LGBT community.
In New York's Washington Square park, several hundred people gathered to protest Trump's election.
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More anti-Trump demonstrations are planned heading into the weekend, according to organisers' online posts. One urged protesters to rally in Washington, DC, on Inauguration Day.
Supporters of Trump, who surprised many in the political and media establishment with Tuesday's win, urged calm and recommended that Americans wait to see how he performed as president.The United States has seen waves of large-scale, sometimes violent protests in the past few years.
Students at the University of Texas at Austin lead a protest down to Congress Bridge in Austin, Texas. (AAP) Source: AAP
Cities from Ferguson, Missouri, to Berkeley have been rocked by demonstrations following high-profile police killings of unarmed black men and teens. Those followed a wave of large-scale protest encampments, starting with the Occupy Wall Street movement in New York in 2011.
Trump said in his victory speech, which was delivered in a far calmer manner than he displayed in many campaign appearances, that he would be president for all Americans.
Some of his most controversial campaign proposals, including the call to ban Muslims from entering the United States, had been removed from his campaign website by Thursday.