D.C. officials think a demonstration planned for Saturday by far-right groups supporting the rioters who stormed the U.S. Capitol on Jan. 6 will prove to be a small gathering, attracting no more than a few hundred people.

But city leaders are worried that those who do attend may bring firearms illegally, setting up the potential for clashes in an area expected to be bustling on Saturday with crowds at multiple events: the annual H Street festival in Northeast that typically attracts thousands; a Howard University football game at Audi Field in Southwest; a baseball game at Nationals Park; and a Harry Styles concert at Capital One Arena downtown.

“This is a great day for the city. This is showing that we’re open and folks can come here and do everything” from taking in a sports game or a show to attending a political protest, said Deputy Mayor for Public Safety and Justice Christopher Geldart on Tuesday. “It’s really what the city’s about.”

But Geldart also acknowledged the concerns. As he spoke, more than 30 staff members from Democratic Mayor Muriel E. Bowser’s office walked the blocks on H Street NE that will host Saturday’s festival. They stepped into each business on the commercial corridor to offer window signs noting that guns are prohibited inside.

“If you see someone with a firearm, immediately call 911,” some of the signs said. Proprietors of restaurants, pharmacies and gyms accepted the fliers.

Geldart said he and other D.C. public safety officials have been monitoring social media conversations relating to the far-right protest. “There are calls on some of the disparate sites for folks to come armed,” he said. D.C. regulations make it illegal for most nonresidents to carry guns in the city, a law that the mayoral staff members brought up in their conversations with H Street workers.

Geldart said that U.S. Capitol Police Chief J. Thomas Manger has asked some suburban jurisdictions to send officers to help the Capitol Police keep order during the demonstration, which will be near the reflecting pool on the west side of the Capitol and has permit clearance for 700 people.

Capitol officials plan to put up fencing to protect the building. After the riot in January, the Capitol grounds were fenced for months, much to the frustration of D.C. residents who pass through the area on their commutes and enjoy the grounds as a place for recreation. This time, Manger has said the fences probably will come down soon after Saturday’s demonstration.

Geldart said the D.C. National Guard has not been activated, but Capitol Police leaders have discussed with Army officials whether the Guard might be available to respond quickly in the event that more personnel become necessary.

The entire D.C. police force has been called to work on Saturday, and Geldart said officers will be focused on protecting residents at the major festivals and gatherings happening across the city on Saturday, including potential left-leaning counterprotests at Freedom Plaza, a dozen blocks from the Capitol.

“I’m hoping this is a great weekend for everybody. I hope folks are able to come to their nation’s capital and peacefully express their First Amendment views,” he said.

He predicted that the demonstration, which is billed as a show of support for the people arrested in the deadly riot in January, will draw a crowd even smaller than its permit allowance, and said Capitol Hill residents should feel secure in their neighborhood even as the demonstrators assemble.

“Folks should be able to come out in their city this weekend,” he said. “Folks are safe.”