Police in riot gear have attempted to keep groups of protesters lining the route of the presidential parade apart, with video showing people wearing black hoods running through streets in the capital and overturning bins.
Demonstrators wearing orange jumpsuits with black hoods over their faces - representing prisoners in the US detention facility at Guantanamo Bay - were earlier at one security checkpoint.
Other groups including Black Lives Matter and feminist organisations were among other protesters ahead of the ceremony.
More demonstrations are expected to take place as the inauguration unfurls, including a DisruptJ20 march from Columbus Circle outside Union Station to McPherson Square three blocks from the White House.
Filmmaker and liberal activist Michael Moore will feature in a rally at the square.
The ANSWER Coalition anti-war group is planning to stage demonstrations along the parade route.
Supporters of Mr Trump lined up at checkpoints before dawn to take their places along the route of the parade, with cheers heard as he arrived at the White House with wife Melania where he met with Barack Obama.
Around 900,000 people are expected to pack the National Mall facing the Capitol, where Mr Trump will be sworn in, as well as the route.
Some of the demonstrations attempted to block access to the checkpoints.
Clashes took place on Thursday evening outside the National Press Club in central Washington DC, with police using chemical spray to disperse protesters.
Further protests are planned for Saturday, when a massive Women's March on Washington will take place.
Demonstrations on Inauguration Day are not unique to Mr Trump's candidacy.
Richard Nixon's first and second terms drew memorable protests, with demonstrations over the Vietnam War before his second stint in the White House.
During President George W Bush's inauguration in 2001, demonstrators turned their back as the president passed by along the parade route, with others holding signs including "Hail To The Thief" in reference to his election over Democrat Al Gore.
Source: Skynews
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