Hundreds protested Donald Trump in New York and blocked a major road in the southwestern state of Arizona, where a demonstrator was punched and kicked at a rally.
The latest attempts by opponents to disrupt the campaign of the top US Republican White House hopeful resulted in a handful of arrests, police and witnesses said.
In Tucson, Arizona a protester with a sign showing Trump's face and the words "Bad For America," was kicked and punched by a member of the audience while being escorted out of the venue by security, video posted online by NBC showed.
The network reported that the audience member was handcuffed and taken away before being charged with assault with injury, according to police.
Meanwhile, on the other side of the country, demonstrators who gathered at Manhattan's Columbus Circle, near one of the billionaire real estate mogul's luxury buildings overlooking Central Park, shouted the slogan "Donald Trump, go away, racist, sexist, anti-gay."
Amid a considerable police presence, protesters held up signs that read "Deport Trump" and "Build a wall around Trump."
Also spotted in the crowd were placards which read "Don't let bigotry Trump our constitution" and "Will trade 1 Donald Trump for 25,000 refugees."
At least one person was arrested on the city's famous Fifth Avenue during a brief skirmish that was quickly brought under control by police.
The demonstration was organized by a group called Cosmopolitan Antifascists, with others joining in. Ordinary New Yorkers turned out for the event, concerned by Trump's status as the clear frontrunner for the Republican party's nomination ahead of November's presidential elections.
Trump "is racist, he is sexist, he is homophobic, he is Islamophobic, xenophobic, he is a fascist. It has serious implication for the future of America," Patrick Waldo told AFP.
"If we start closing our borders to some people based on their religious beliefs, that is completely unconstitutional... we start going to a World War II Germany kind of situation and I don't want that in my country," the 31-year-old historian added.
Trump has called for a ban on all Muslims entering the United States, just one example of rhetoric by the candidate that has sparked controversy on the 2016 campaign trail.
"Everything he says is racist, is false. It hurts my feelings," said Nour Hapatsha, a 22-year-old Muslim born in the United States.