WASHINGTON (AP) — President Donald Trump will personally address a gathering of his supporters in Washington Wednesday as he seeks to rally populist support for his last-ditch efforts to overturn his loss to President-elect Joe Biden.

The White House confirmed Tuesday that Trump will speak at a rally on the Ellipse just south of the White House. The protests coincide with Wednesday’s congressional vote expected to certify the Electoral College results, which Trump continues to dispute.

The rallies have local officials bracing for potentially violent street clashes. With downtown D.C. businesses boarding up their windows, Mayor Muriel Bowser has requested a limited National Guard deployment to help bolster the Metropolitan Police Department. During a press conference Monday, Bowser urged local area residents to stay away from downtown D.C. and avoid confrontations with anyone who is “looking for a fight.” But, she warned, “we will not allow people to incite violence, intimidate our residents or cause destruction in our city.”

Election officials from both political parties, governors in key battleground states and Trump’s former attorney general, William Barr, have said there was no widespread fraud in the election. Nearly all the legal challenges from Trump and his allies have been dismissed by judges, including two rejected by the Supreme Court.

A pro-Trump rally Dec. 12 ended in violence as hundreds of Trump supporters, wearing the signature black and yellow of the Proud Boys faction, sought out confrontations with a collective of local activists attempting to bar them from Black Lives Matter Plaza, an area near the White House. At least two local Black churches had Black Lives Matter banners torn down and set ablaze.

On Monday, MPD officers arrested the leader of the Proud Boys, Henry “Enrique” Tarrio, 36, after he arrived in Washington ahead of this week’s protests. Tarrio was accused of burning one of the Black Lives Matter banners in December.

Organizers planned to rally Tuesday evening at Freedom Plaza and again all day Wednesday on the Ellipse, including a 1 p.m. Wednesday march to the Capitol. Expected attendees include high-level Trump supporters like Texas Attorney General Ken Paxton and Republican strategist Roger Stone, a longtime Trump devotee whose three-year prison sentence was commuted by Trump. Stone was convicted of repeatedly lying to Congress during the investigation into Russian interference in the 2016 election.

A November pro-Trump rally drew about 15,000 participants. The Dec. 12 rally drew smaller numbers, but a larger contingent of Proud Boys.

At previous pro-Trump protests, police have sealed off Black Lives Matter Plaza itself, but the confrontations spilled out to the surrounding streets. Acting Police Chief Robert Contee on Monday said sealing the area again was “a very real possibility” but said that decision would depend on the circumstances.

“We know that historically over the last few demonstrations that BLM Plaza has been a focal point,” Contee said. “We want to make sure that that is not an issue.”