Anti-government protesters have described Exco member Fanny Law's claims that young girls are misled to give free sex to front-line protesters as an insult to the intelligence of Hongkongers.
Speaking at the self-styled Citizens' Press Conference on Monday evening, the protesters said Mrs Law didn't back her claims with evidence, and called on her to report the matter to police if she has proof.
"This is another example of the state campaign against protesters and this shows the quality of the government," said a protester who calls himself Ezra Chan.
"Without legitimately responding to our demands, they have chosen to launch a smear campaign against everyone and this is why we're against fake news," he said.
Mrs Law made the comment on RTHK's "Backchat" programme on Monday morning.
Reacting to a listener's email which alleged that some girls are being tasked to provide "comfort" to frontline protesters, Law said: "I think we have confirmed that this is a true case. I am so sad for these young girls who have been misled into offering free sex."
Law's claim prompted an angry listener to call into the show, accusing her of spreading rumours and disrespecting people.
"There is evidence. That is the daughter of a friend's friend. That's second-hand knowledge, but it's direct, it's real. Okay? Direct and it's real. And the girl actually wrote a piece," Law said.
But the caller, who gave his name as Matthew, was not satisfied with the response: "This is outrageous. It's just too much, Fanny".
"Where are these emails coming from, Fanny? You know as well as I do how the United Front machine works," he said.