The protesters favoring Trump clashed in the streets with counter protesters hours later, after night fell in the capital.
One person was stabbed, two police officers were injured and several firearms were also recovered by police, according to the reports.
At least 20 people were e arrested by police on a variety of charges, including assault and weapons possession.
On the other hand, Trump reiterated his claims of widespread voter fraud in the election although senior US federal and state election officials rejected the claims, saying “the November 3 election was the most secure in American history”.
“There is tremendous evidence of wide spread voter fraud in that there is irrefutable proof that our Republican poll watchers and observers were not allowed to be present in poll counting rooms. Michigan, Pennsylvania, Georgia and others. Unconstitutional!,” Trump tweeted on Sunday.