Washington (CNN) A Mississippi Republican gubernatorial candidate on Thursday stood by his decision to deny a female reporter's request to accompany him on a campaign trip unless she brought along a male colleague, a move that she says amounts to "sexism."

"I didn't want to end up in a situation where me and Ms. Campbell were alone for an extended period of time throughout that 15- or 16-hour day, and so out of precaution, I wanted to have her bring someone with her -- a male colleague. The other thing I think it's important to point out is that this is my truck, and in my truck, we go by my rules and that's my rule," state Rep. Robert Foster told CNN's John Berman on "New Day."

Larrison Campbell, a reporter for Mississippi Today who was denied the hours-long interview by Foster, expressed frustration with the situation during the same CNN interview.

"Look, we got to call this what it is: when a woman isn't given access to the same things that a man would be given access to, it's sexism," she said.

Campbell wrote in Mississippi Today on Tuesday that the paper had asked to shadow each gubernatorial candidate seeking the GOP nomination "in an attempt to better inform readers" and that the other two candidates agreed to the request while Foster declined.

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