WASHINGTON: Hundreds of Donald Trump's supporters began massing in Washington on Tuesday, a day ahead of a protest called by the outgoing US president who refuses to concede defeat in November's election.

Coming from all corners of America, the demonstrators said they had answered Trump's appeal to gather in the capital Wednesday, when the US Congress is expected to certify President-elect Joe Biden's election victory.

"My commander-in-chief called me and my Lord and Savior told me" to come, said Debbie Lusk, 66, a retired accountant from Seattle.

"We either take our country back, or it is no more," she told AFP.

Trump has confirmed he will address the rally, urging followers on Twitter to "arrive early" for his 11:00 am (1600 GMT) speech, to be given at a site near the White House.

Last month he tweeted that supporters should head to Washington for what he promised would be a "wild" day of protests.

Large parts of the downtown area were boarded up, with shops and businesses shuttered by the virus and amid fears of a repeat of the violence that rocked the city during racial-justice protests last year.

Trump has refused to accept his election loss, making repeated and unfounded claims of fraud or vote rigging in the states where he was narrowly beaten. Various courts have rejected legal challenges from Trump's team.

More than half of Republican voters believe Trump won or aren't sure who did, according to a survey last month from researchers at top US universities, including Harvard.

That confusion was echoed by many of the mainly upbeat supporters who had gathered under grey skies at a chilly Freedom Plaza near the White House on Tuesday.

"We don't trust the outcome of the elections," said Chris Thomas, 69, a retired saleswoman wearing a Trump hat.

Thomas told AFP she and her husband had come from Oregon because they "believe in the freedom of America", and to show support for Trump's economic policies that helped their son's wine-chiller business prosper.

Warming up the crowd with speeches on Tuesday were longtime Trump advisor Roger Stone and former national security advisor Michael Flynn, each recently pardoned by Trump after being swept up in connection to special counsel Robert Mueller's probe into whether the Trump campaign conspired with Moscow.

Flynn warned members of Congress: "Those of you who are feeling weak tonight, those of you who don't have the moral fiber in your body, get some tonight because tomorrow we the people are going to be here and we want you to know that we will not stand for a lie."

Few masks

Several of them said the media had exaggerated the severity of the Covid-19 pandemic, which has killed more than 355,000 people in the US.

Vice President Mike Pence is to preside over Wednesday's joint session of Congress, in which lawmakers will count and confirm the state-by-state Electoral College votes that decide the presidency.

That certification is usually a formality, but Trump has been pressuring his loyal deputy to overturn Biden's win by falsely claiming Pence has the authority to discard pro-Biden votes.

"It would really surprise us if Pence doesn't back Trump," Thomas, the retired saleswoman, said.

Many demonstrators were hoping for a last-minute surprise that would keep Trump in power beyond January 20, the date of Biden's inauguration.

"Trump won by far. There's more than enough evidence," said Matthew Woods, 59, from California.

Anthony Lima, also from California, said he had traveled to Washington because he wanted to see for himself what was happening.

"A lot of news agencies don't tell us the truth," he said. "I am open to believe Joe Biden and Kamala Harris won the election, I just want an investigation."