The Trump campaign promoted an outlandish false claim on Monday that Haitian immigrants in Springfield, Ohio, have abducted and eaten their neighbors’ pets, again demonizing migrants as the campaign seeks to attack Vice President Kamala Harris on immigration.

A news release from the campaign on Monday recounted the falsehoods, which were amplified earlier in the day by former President Donald J. Trump’s running mate, JD Vance, and sought to stoke fear, saying “it’s coming to your city next.”

Mr. Vance, as Ohio’s junior senator, has in recent months attacked the growing Haitian population in Springfield, a group whose members are living and working in the United States legally. Job opportunities in Springfield have attracted thousands of Haitians since the pandemic, with city officials estimating that as many as 20,000 have arrived. By most accounts, the immigrant community has helped revitalize the town, though it has put pressure on housing, schools and hospitals. (Springfield had roughly 58,000 people as of the last census in 2020.)

Resentment has also brewed among some residents over the immigrants’ presence, and those emotions bubbled over recently after an immigrant driver was involved in a fatal school bus crash. Mr. Vance has latched onto the complaints of community members and has denounced the Haitians as being in the United States illegally, “draining social services” and “generally causing chaos.”

Other prominent Republican elected officials and organizations, including Senator Ted Cruz of Texas, the House Republican campaign arm and the Republican-led House Judiciary Committee, promoted false claims about pets or park wildlife being eaten on Monday.