Washington: US civil rights activists kicked off a week of protests ahead of Donald Trump's presidential inauguration with a march in Washington on Saturday, vowing to keep fighting for equality and justice under the upcoming administration.

Chanting "no justice, no peace," a few thousand protesters headed by the Reverend Al Sharpton marched along the National Mall toward the Martin Luther King Jr. Memorial, about 3km from the steps of the US Capitol, where Trump will be sworn in as president on Friday.

Pre-march speakers denounced Trump to protesters, who braved drizzle and temperatures just above freezing to show their support for minority rights and President Barack Obama's signature healthcare law, which Trump has vowed to dismantle.

"We stand together, not as a people of hate, but as a people of hope," said Charley Hames Jr., president of the Oakland, California, chapter of Sharpton's National Action Network. "We believe this march is the first of many."