
Washington police arrested more than 90 people over acts of vandalism committed on the fringe of peaceful citywide demonstrations being held against Trump's inauguration.
Just before the parade started, clashes broke out between 400 to 500 stone-throwing protesters and riot police, who responded with tear gas -- the second violent flare-up in the space of a few hours.
As Trump's motorcade wound its way up Pennsylvania Avenue in the parade to the White House, protesters just a few blocks away set a parked limousine on fire after smashing its windows.
An AFP reporter saw National Guardsmen donning helmets and bullet-proof vests, as protesters blocked traffic and set trash cans ablaze -- chanting "Not my president" and "We resist President Trump."
Earlier, masked youths emerged from crowds of peaceful protesters to kick over trash cans and smash windows of stores, a bank and a fast food outlet.
Two police officers sustained minor injuries and around 95 people were arrested for vandalism and destruction of property.
As the 70-year-old Trump, his supporters and top dignitaries gathered on the National Mall for the swearing-in ceremony, throngs of his opponents also converged on the US capital.
Most of the noisy protests -- including those by an array of anti-racist, feminist, LGBT, pro-immigration, anti-war and marijuana legalization groups -- were peaceful.
But the protesters were intent on being heard -- massing at the city's Navy Memorial Plaza, along the parade route, and letting out a deafening roar as the presidential limousine known as "The Beast" drove by.
"Not my president! Not my president!" they yelled, as the pro-Trump crowd in bleachers across the street chanted "USA! USA!"
Protesters along the route waved banners reading: "Try to deserve this office," "Obama cares, Trump scares," or "Make America Sane Again."
Another group unfurled a giant banner reading "Shame" outside the Trump Hotel -- right near the spot where the president briefly stepped out of his limo to walk the parade route.
- 'No fascist USA!' -
=====================
DC police chief Peter Newsham attributed the sporadic outbreaks of violence to "a small group that wanted to disrupt the inauguration."
"We have significant damage in a number of blocks in our city," he said, while adding: "It's a very, very small percentage of those folks who came here to peacefully assemble in our city."
Black-clad groups with anarchist and anti-fascist banners could be seen moving at speed on the outskirts of the main protests.
Marchers, some red-eyed from pepper spray, chanted: "No deportation, no KKK, no fascist USA!"
Several demonstrators were carrying batons and other weapons, police said, while at least one protester was hurt and was seen receiving treatment for a head wound.
The front windows of local businesses including a Starbucks and a Bank of America were smashed to pieces.
"To those of you visiting Washington, DC, we welcome you but we cannot allow you to destroy our neighborhoods," tweeted city mayor Muriel Bowser.
- 'Sad day' to be American -
============================
The majority of protests in the city were peaceful however -- whether people came to register anger, dissent or dismay at Trump's election victory over Hillary Clinton.
Groups of Trump supporters passed by the protests on the way to hail their hero, and some insults were thrown, but the two sides kept largely apart.
One sign showing a smiling image of Russian President Vladimir Putin read: "Putin's pick is nyet my president."
A 27-year-old financial worker from Tampa Bay in Florida, who did not want to give his name for fear of retaliation by his employer, said he was fearful for the future.
"There is nothing to hope for except for grassroots efforts to oppose him," he told AFP.
Protesters said they feared Trump would be an extremist president, taking a hardline approach on everything from immigration to gutting public services.
"It's a sad day to be an American," said 26-year-old Washington resident Colin Hernandez.
Public interest lawyer Renee Steinhagen, 61, came down from New York to join the protests.
"This is a simple act of resistance. It's better than staying at home," she said.
John Zangas, a longtime DC resident, said it felt like the city was "under siege" given the number of police on the streets.
"This should be a momentous occasion, not one where flash-bang (noise grenades) and teargas are deployed against citizens," Zangas said.