Those ads, The Post said, seemed to target minority voters.
Loyola University Chicago associate professor of physics Robert McNess was among the first on Twitter to report the user and the fake ads. According to McNess, he received word from Twitter that the tweets did not violate the site's terms of service.
The Post reported that the tweets were later removed and some accounts spreading the fake ads had been suspended.
Twitter CEO Jack Forsey said in a reply to McNess that he was "not sure how this got past us," but that it had been "fixed."
Anyone who does text "Hillary" to 59925, according to Mashable and BuzzFeed News, will get this message:
"The ad you saw was not approved by iVisionMobile OR Hillary For America in any way. To opt-in to the real HFA list, text HFA to 47246. Reply STOP to cancel."