Former President Donald Trump and running mate JD Vance’s unfounded claims about Haitian immigrants in Springfield, Ohio weaken the Republican Party’s border message, Ohio Governor Mike DeWine wrote in an op-ed published Friday.

“The Biden administration’s failure to control the southern border is a very important issue that Mr. Trump and Mr. Vance are talking about and one that the American people are rightfully deeply concerned about,” DeWine, a Republican, wrote in the New York Times.

“But their verbal attacks against these Haitians — who are legally present in the United States — dilute and cloud what should be a winning argument about the border,” he said.

The perception that President Joe Biden and Vice President Kamala Harris have failed to stem the tide of asylum seekers ant the souther border has long been a key message for Republicans up and down the ballot, not just for Trump’s reelection campaign.

Trump’s latest immigration claims thrust Springfield, Ohio into the national spotlight, after he and Vance — who represents Ohio in the Senate — promoted unfounded rumors that Haitian immigrants were stealing and eating city resident’s pets.

DeWine and local officials have repeatedly denied the claims.

“As a supporter of former President Donald Trump and Senator JD Vance, I am saddened by how they and others continue to repeat claims that lack evidence and disparage the legal migrants living in Springfield,” DeWine, who was born in Springfield, wrote Friday.

“This rhetoric hurts the city and its people, and it hurts those who have spent their lives there.”

In the days since Trump and Vance promoted the unfounded rumors — which the Trump campaign knew were false, according to the Wall Street Journal — dozens of bomb threats have led to Springfield city schools to be evacuated and closed.

DeWine on Monday announced that Ohio state police would begin conducting sweeps of city schools every morning and night. The threats, which officials have found to all be hoaxes, have also targeted city government buildings and a local hospital.

William Martin, a spokesperson for Vance, told NBC News that the Republican vice-presidential nominee “is glad” that Dewine supports the Trump-Vance campaign, but Vance and DeWine are “not always going to agree on every issue.”

In his op-ed, DeWine emphasized the role Haitian immigrants played in reviving Springfield’s economy, which he said experienced “tough times” in the 1980s and 90s.

“Now, however, Springfield is having a resurgence in manufacturing and job creation. Some of that is thanks to the dramatic influx of Haitian migrants who have arrived in the city over the past three years to fill jobs.”

“They are there legally. They are there to work.”