A Minnesota bar has been shuttered following mass resignations after staff learned its owner donated to former KKK grand wizard David Duke's 2016 U.S. Senate campaign.

"Half the people were in tears," Club Jäger trivia host Rob Callahan told Minneapolis' City Pages newspaper regarding his colleagues after news of owner Julius De Roma's $500 donation to Duke last October broke. "And the other half were pretty much punching walls."

Staff received threatening messages and one of Club Jäger's servers was chased down a street, spat at, and called "Nazi", Callahan said. At the same time, new customers turned up at the bar in support of De Roma, prompting staff to quit on Thursday, he added.

De Roma, who owns a number of properties in Minneapolis, told CBS-affiliate WCCO his donation was a matter of "free speech."

"Well, whatever," De Roma said. "What do you expect? It's basically something that is blown up beyond what it should be."

Duke unsuccessfully ran for a U.S. Senate seat in Louisiana. He previously served as a member of the state's legislature from 1989 to 1992.