Ukip has hit out at social media users who spread "scurrilous opinions" claiming to be speaking for the party using fake Twitter accounts.
Roger Helmer, a MEP for the eurosceptic party, made the remarks after a storm over offensive tweets about World AIDS Day from an account that claimed to represent the party's Cheltenham branch.
The tweets, sent by @UkipCheltenham, said AIDS was not something Britain had "before we opened our borders to all".
Mr Helmer said it was part of a "Twitter scam" to trick voters about what Ukip's policies were. He also referred to another account that last weekend claimed to represent Ukip in London and posted messages saying homosexuality "goes against nature".
The Cheltenham account also said the issue was "about our women who throw themselves at African men unknowingly".
The disease came to Britain because of "Africans and Asians coming into the UK through tourist visas and remaining illegally", it said.
Although the account insisted it spoke for "Ukip supporters in Cheltenham", the local party distanced itself from it, claiming it was fake.
It appears to have been active only since November 28 and had just 70 followers at the time of writing.
John Hopwood, membership secretary of Cheltenham Ukip branch, told The Gloucester Citizen: "We categorically deny that this is anything to do with Cheltenham Ukip.
"We do not have a Twitter account. We have checked and this is nothing to do with anyone in the Cheltenham party, so this is some sort of troll account.”
The account later apologised for the offence the AIDS tweet caused but maintained "we need to look beyond this and at our borders".
It also insisted it was not a "fake account" after numerous articles were published saying it was.
@UkipCheltenham's initial tweet triggered a barrage of attacks, including one person who suggested whoever was behind it "stop breathing for four minutes".
While the growing consensus is that @UkipCheltenham is fake, or at least not formally affiliated with the party, Nigel Farage has suggested before that HIV positive foreigners should be barred from entering the UK.
Yusef Azad, Director of Policy at the National AIDS Trust, said the majority of HIV diagnoses in the UK are of people who acquired it here.
When asked about the @UkipCheltenham tweet, he told The Huffington Post UK: "The HIV epidemic was affecting substantial numbers in this country well before migration had any effect on numbers.
"The closing of borders is not something supported by international agencies and is not believed to be a sound approach to controlling the epidemic.
"HIV is spread by fear, by unwillingness to talk about it or get tested, by blame, stigma and the marginalisation of vulnerable groups."
He added: "This sort of statement (by @UkipCheltenham) is sadly all too common in some other parts of the world – as a result, those places have much higher rates of HIV than we do."