Washington (CNN) Former 2016 Green Party presidential candidate Jill Stein slammed Hillary Clinton's accusations that she and 2020 Democratic candidate Tulsi Gabbard are Russian assets, calling Clinton's comments a "wild and insulting theory."

"I am not a Russian spy," Stein said Saturday on CNN's "Smerconish." "I think this is a completely unhinged conspiracy theory for which there is absolutely no basis in fact. Not for myself and not for Tulsi Gabbard. I think it's really outrageous that Hillary Clinton is trying to promote this crazy idea."

She added, "You know, you can't just slander people. You have to present some basis and fact."

Speaking on a podcast Thursday, Clinton accused Stein of being a "Russian asset." She also claimed the Russians are currently "grooming" a Democrat running in the 2020 presidential primary to run as a third-party candidate and champion their interests. Though she never names Gabbard , Clinton's comments appeared to be aimed at the Hawaii congresswoman.

Stein told CNN on Saturday that Clinton's remarks "speaks to Hillary's need to try to explain, perhaps to herself, why her campaign was not successful."

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