Mr. Trump claimed there were “25,000 people who wanted to be here tonight,” and blamed Democratic leaders like Keith Ellison, the state’s attorney general, for preventing his supporters from gathering.

Gov. Tim Walz of Minnesota, a Democrat, limited gatherings to fewer than 250 people. Mr. Trump lashed out at Mr. Walz and Mr. Ellison, claiming his supporters were “barred from entry by radical Democrats.”

“Keith Ellison and Joe Biden want to imprison you in your homes,” he said, “while anarchists roam free.” The president added, “the Democratic Party wants you to be banned from peaceful assembly while they allow their supporters to burn down a police precinct.”