A gun shop in North Carolina has erected an advertising billboard invoking an apocalyptic prophesy to mock the progressive Democrats Alexandria Ocasio-Cortez of New York, Ilhan Omar of Minnesota, Rashida Tlaib of Michigan and Ayanna Pressley of Massachusetts in what anti-gun violence advocates call an incitement to violence.

The billboard, which went up over the weekend, puts images of the four progressive Democratic congresswomen under the phrase “The 4 Horsemen Cometh”, and goes on to describe them as “idiots”.

The Cherokee Guns’ owner, Doc Wacholz, has denied that the billboard on Route 64 outside Murphy is a deliberate provocation. “I’m not inciting any violence or being racist. It’s a statement. It’s an opinion,” he told the Asheville Citizen Times.

However, he then made racist and incorrect statements about the four leftwing congresswomen of color.

“They’re socialists, from my point of view. I also feel a couple of them, being Muslim, have ties to actual terrorists groups,” he said.

The signage joins previous Cherokee Guns billboards that have depicted words or images designed to denigrate Muslim Americans.

In 2017, the store posted an ad for “INFIDEL ARMAMENT” it read in block letters above Arabic script and a rifle. In 2015 the Asheville Citizen-Times reported a billboard that said: “Give me your tired, your poor … Keep your Syrian refugees.”

The incident comes after Donald Trump issued provocative tweets telling Omar, who is Somali American, and her colleagues to “go back” to where they came from. The four congresswomen have become known as “the Squad” and are prominent and vocal critics of the president.

But some groups warned that Wacholz’s advert is a step toward actual violence.

“Threats against members of Congress, particularly minority members, are [trending upward] and it is driven by the president’s racial rhetoric,” the Coalition to Stop Gun Violence wrote in a statement. “This is dangerous!!!”

Ilhan Omar, Ayanna Pressley, Alexandria Ocasio-Cotez and Rashida Tlaib during a press conference on Capitol Hill on 15 July. Photograph: UPI/Barcroft Media

In a tweet on Wednesday evening, Tlaib asked how the billboard could not be considered an aggressive inducement.

“How the hell is this not inciting violence?” she wrote.

Pressley tweeted: “#Racist rhetoric from the occupant of the @WhiteHouse has made hate our new normal. We are still vulnerable.”

But appeals for civility appear to be falling on deaf ears. Wacholz amped up his attack when the store posted a statement on Facebook that said it planned to produce clothing with the billboard’s image.

“Alright my fellow Infidels for Trump … due to OVERWHELMING demand … you may come by the shop (next week) and get your very own FOUR HORSEMEN COMETH STICKER … simple … eat a piece of bacon … tell us you’re voting for Trump in 2020 … then get your limited edition bumper sticker! (While supplies last!) Snowflakes and Liberals are not eligible … sorry ...”