Demonstrators march following the election of Donald Trump as President of the United States through Oakland, California, US November 9, 2016.[Photo/Agencies]

Young people, mostly students, held protests across California on Wednesday after Donald Trump was elected the 45th president of the United States, according to media reports.

Shortly after Trump declared his victory, 1,500 to 3,000 people left their dormitories or apartments, protesting against the presidential election results at University of California at Los Angeles (UCLA).

Videos from the scene showed that the students were chanting "not my president" in a march on the UCLA campus.

Republican presidential nominee Trump, 70, won Tuesday's presidential election in the United States and is set to succeed Democratic Barack Obama as the next U.S. president.

"There's nothing destructive...Just students exercising their First Amendment right. We're just monitoring them but they've been fully cooperative," Sgt. Miguel Banuelos of the UCLA Police Department told local media.

"The University of California is proud of being a diverse and welcoming place for students, faculty and staff with a wide range of backgrounds, experiences and perspectives," according to a statement from UC President Janet Napolitano and the chancellors of UC campuses.

About 200 people demonstrated near Cal State L.A., and about 300 others participated in a peaceful march at UC Irvine, which started at a university shopping center, then moved across the campus.

In downtown Los Angeles, 200 to 300 teenagers and young adults rallied outside the City Hall.

Some property was defaced, including a fence scrawled with graffiti insulting Trump. Some demonstrators chanted "Not my president," and at least one held a sign that stated: "Trump Equals Death", according to City News Service.

Protests also formed in other cities in southern California. At UC Santa Barbara, hundreds marched near the campus shortly after Trump delivered his victory speech, "Not my president." Some of them were waving Mexican flags, worrying about Trump's immigration policy, according to a video posted by the students.

At UC San Diego, an estimated 500 students marched through the La Jolla campus.

Smaller groups were also seen at other University of California campuses and neighborhoods in Davis and at California State University, San Jose.

In northern California, students on Wednesday also spoke out loud their outrage about Trump's victory.

Thousands of Berkeley High School students walked out of class Wednesday morning and pledged to unify, according to posts on social media.

After marching through downtown Berkeley, students used a bullhorn to speak their strong opposition to the Republican president-elect, according to UC Berkeley.

At noon, undocumented UC Berkeley students and their allies, joined by some of the high school crowd, protested again, under a huge banner that read "Undocumented, unafraid."

In Bay Area, hundreds of anti-Trump protesters, who predominantly appeared to be students and other millennials, poured onto streets early Wednesday morning. The protesters blocked freeways, lighted fires and shouted, "Not our president", according to L.A. Times.

The protesters burned Trump effigies and chanted his name with expletives. They also smashed windows and set garbage bins on fire early Wednesday in downtown Oakland.