A Republican operative claims a Port Authority police official repeatedly kicked him in the groin on a Midtown street when he name-dropped Donald Trump — and the high-ranking cop has been suspended amid an investigation by his agency and the Manhattan DA, law enforcement sources told The Post.

“I’m a friend of Donald Trump,” Arcadio Casillas allegedly told Deputy Inspector John Fitzpatrick, who pulled over the cab he was riding in on Jan. 9.

“You are a bad cop,” Casillas said, according to the sources. “I know Donald Trump. I will have your job for this.”

The name-dropping led to a full-blown fight in the street that ended with Casillas on the ground with his pants split open, the political fundraiser claims.

The evening began with Casillas, who stepped down as the finance chair of the state Republican Party in December, at the ritzy Union League Club on East 37th Street — at the same time as Fitzpatrick, sources said.

The Port Authority police official was allegedly eating dinner with two police buddies and a civilian.

It’s unclear if they interacted inside, but he and Casillas left at nearly the same time. The former GOP delegate took a cab, and Fitzpatrick drove away in his unmarked PAPD car, sources said.

At some point, Casillas’ cabbie cut Fitzpatrick off — causing him to throw on his police lights.

When Fitzpatrick pulled the car over and confronted the driver, the Trump supporter snapped — hopping out of the back seat and ranting about how the cop was delaying his ride, sources said.

After dropping Trump’s name, a fight ensued between the pair, and Casillas claims Fitzpatrick kicked him several times in his groin, the sources said.

The cabbie, meanwhile, drove away and left Casillas ranting and raving in the street, the sources said.

Casillas finally agreed to step back onto the curb — but tumbled to the ground and split his pants, sources said.

Sources said Casillas was later taken to the hospital and treated for his injuries.

He later reported his account of the incident to the Port Authority, sources said.

Fitzpatrick has since been suspended without pay. The Manhattan’s DA’s Office is investigating the incident, as well as the Port Authority’s inspector general, sources said.

Fitzpatrick’s lawyer, Marvyn Kornberg, said his client is “innocent of any misconduct.”

The Port Authority PD also declined to comment, and Casillas did not return calls.

Casillas had been a delegate at the Republican National Convention last year.

Over the summer, he joined several Hispanic leaders in endorsing the president — saying he ultimately forgave the “incendiary” comments Trump made about Mexicans in the past.

“They say the Republican Party is racist,” Casillas told Fox News Latino in July. “I don’t buy that, and I’m Latino. Trump is not your typical politician. Democrats and Republicans alike have lost touch with the working people.”

Additional reporting by Carl Campanile