WASHINGTON — A North Carolina GOP office was firebombed early Sunday while the culprits marked their hate for the party by spray-painting the words “Nazi Republicans.”

Hillsborough police are investigating the overnight attack on the Orange County Republican Party office that one GOP official called an “act of political terrorism,” according to the Charlotte Observer.

A flammable material was tossed through the front window of the HQ, setting it ablaze, while the vandals wrote hate graffiti of a swastika and “Nazi Republicans leave town or else” on an adjacent building, the police said.

Photos show extensive damage of broken glass, scorched GOP lawn signs, blackened walls and charred furniture.

“The office itself is a total loss,” said Dallas Woodhouse, executive director of the state GOP. “The only thing important to us is that nobody was killed, and they very well could have been.”

North Carolina is a key swing state in the presidential race that both Hillary Clinton and Donald Trump have spent much time and energy trying to win.

Local police are working with the Bureau of Alcohol, Tobacco, Firearms and Explosives to find those responsible.

“This highly disturbing act goes far beyond vandalizing property; it willfully threatens our community’s safety via fire, and its hateful message undermines decency, respect and integrity in civic participation,” Hillsborough Mayor Tom Stevens said in a statement.

Trump later laid blame on supporters of his opponent, tweeting: “Animals representing Hillary Clinton and Dems in North Carolina just firebombed our office in Orange County because we are winning @NCGOP.”