The Democratic mayor advised residents not to engage with demonstrators "who come to our city seeking confrontation, and we will do what we must to ensure all who attend remain peaceful."
Bowser reminded the public and anyone attending the rally that firearms are prohibited "within 1,000 feet of any First Amendment activity."
The mayor's statement comes as police have been posting signs near where the rally is set to take place, notifying the public that all firearms will be prohibited. Police said the prohibition on carrying weapons at the rally includes city residents who have a concealed carry permit.
Photos of the notices were posted on Twitter by FOX 5 DC reporter Jesse Burkett-Hall.
The rally coincides with the same week that lawmakers will meet for a joint session to certify the Electoral College results, the last step in cementing Joe Biden’s presidential victory.
President Trump last month promised a "wild" protest in the nation’s capital on Jan. 6, while reiterating his claims that it was "statistically impossible to have lost the 2020 Election."
Trump and his campaign team have disputed the election results and have brought their claims to courts throughout the country, and nearly all of those legal challenges have failed. A group of GOP senators led by Sen. Ted Cruz, R-Texas, have said they will object to Wednesday’s certification of the election results unless there is an emergency 10-day audit of the results by an electoral commission.
Over the weekend, the Washington Post published a recorded phone call of Trump urging Georgia’s Secretary of State Brad Raffensberger to "find" enough votes to reverse the state’s results.
"All I want to do is this. I just want to find 11,780 votes, which is more than we have. Because we won the state," Trump reportedly said.
On Monday, Bowser said some 340 National Guard soldiers were activated while the city prepared for potentially violent protests surrounding Congress's expected vote to affirm President-elect Joe Biden's victory.
A U.S. defense official said Bowser put in a request on New Year's Eve to have guardsmen on the streets from Jan. 5-7, to help with the protests. The official said the Washington National Guard will be used for traffic control and other assistance but they will not be armed or wearing body armor.
There will be about 115 guardsmen on duty at any one time in the city, said the defense official. The official said the soldiers will be used to set up traffic control points around the city and to stand with district police officers at all the city's Metro stops. Acting police Chief Robert Contee said the guardsmen will also be used for some crowd management.
"Some of our intelligence certainly suggests there will be increased crowd sizes," said Contee, adding, "There are people intent on coming to our city armed."
The Associated Press contributed to this report.