In rare interview, daughter of President Islam Karimov claims her mother and sister are part of a plot against her, amid jockeying for position in runup to 2015 election

For years she has led a glamorous and often surreal life as the "first daughter" of Uzbekistan, but now Gulnara Karimova appears to be fighting to stay afloat in a vicious clan war.

In an exclusive and rare interview, she has told the Guardian that other members of her family – specifically her sister and brother-in-law – are conspiring with top officials to bring her down.

The socialite daughter of the ruthless president, Islam Karimov, Karimova has worn an extraordinary number of hats over the years: she has controlled business interests, had diplomatic status, designed her own line of jewellery and even released pop songs under the stage name Googoosha.

But now she says her mother and sister are part of a plot against her aimed at misinforming her father about her activities. "Envy or jealousy always destroys unity, even inside one household," she said.

Analysts struggle to make sense of the opaque world of Uzbek politics and the main players and shadowy intrigues that go on around Karimov. But as the ageing dictator prepares for an election in 2015, it is clear that behind the scenes a fierce battle is raging.

Karimova's words, provided as written answers to questions sent by email, are often allusive or allegorical but nevertheless shed light on the infighting in one of the world's most closed countries.

She accuses unspecified enemies of trying to poison her with mercury, and castigates her father's feared SNB security service, which she says has created a climate of terror. She also makes allegations of corruption against a number of senior figures in the Uzbek regime, which the Guardian cannot report for legal reasons.

Islam Karimov, the Uzbek president. Photograph: Ilmars Znotins/AFP/Getty Images

The first sign that trouble might be stirring was when her sister Lola Karimova-Tillyaeva gave an interview to the BBC in September in which she said she and Karimova had not spoken for 12 years and had "no family or friendly relations".

Karimova-Tillyaeva has her own charity foundation and lives a jetset life from her Geneva base. She denies claims that the wealth she shares with her husband, Timur Tillayev, comes from her family ties.

Karimova-Tillayeva was previously media shy, known only for unsuccessfully suing a French magazine that called her a "dictator's daughter". The surprisingly forthright interview led analysts to speculate that she might be plotting a political career for herself or her husband. Russian officials suggested nearly a year ago that Karimova-Tillayeva was "one to watch" in the battle for influence in Tashkent, according to a diplomatic source in Moscow.

Karimova said her sister's interview was "a highly political move" and an "obvious pre-election statement", and she acknowledged that her sister's words had caused strife within the family.

"Everything started with the BBC interview of my sister," she wrote. "He [Karimov] was pretty upset when I mentioned the BBC interview, and the answers, which in my opinion, were damaging to his name."

She accused her mother, an elusive figure who is rarely seen in public but allegedly has her own business empire, of working together with her sister against her. "Their goals are obviously the same, and nothing unites people better than one aim … I would rather not talk about it as it hurts me to accept that for the sake of tomorrow people can betray their close ones today."

Karimova alleged that a number of Uzbek officials, working in cahoots with her sister and brother-in-law, ordered fake online articles about her, which were then shown to her father as part of "a carefully prepared plan to harm him and to destroy me".

Karimova-Tillyaeva could not be reached for comment on the allegations, and calls and emails to the Uzbek embassy in Paris, where she is currently based as the Uzbek ambassador to Unesco, went unanswered. She has previously rejected allegations made against her by her sister, which she says are defamatory. In a recent statement she said she was considering whether to take legal action over them.

Lola Karimova-Tillyaeva in 2009. Photograph: Sipa Press/Rex Features

Karimova, for her part, denied the extraordinary rumour posted by an Uzbek opposition website that her father, furious, had hit her across the face and banished her from his palace. She claimed there was no tension between them. "I never fought with my dad in any way. We didn't even have an argument lately," she wrote.

Nevertheless, it is clear from some of her other answers that the situation is tense. Karimova speaks of a "terror" against her from elements inside the SNB, claiming that she and her son were the victims of a poisoning attempt back in 2011.

She provided the Guardian with a copy of test results from a German clinic purporting to show high levels of several heavy metals in her blood. She claimed she was poisoned in 2011 while in Uzbekistan, and that there were "only a few people who could have done it". But she did not give any names and she did not suggest that any family members were implicated in the poisoning. She said she still suffered symptoms from the incident.

Whether or not her father is behind any of the alleged attempts to undermined or poison her, Karimova's business, media and charity interests have all come under attack in recent months. She was recalled from her diplomatic posting to Geneva this year after two European corruption investigations came embarrassingly close to her, and she speaks of some of her associates ending up in "the scary SNB detention place where they can do anything with anyone".

Karimova appears to criticise much of the repressive apparatus of her father's state.

Rights activists say that while the brutal methods of Uzbekistan's police and special services need light shone upon them, it is strange that Karimova is the one wielding the torch.

Andrew Stroehlein of Human Rights Watch has carried out a series of often bizarre exchanges with Karimova on Twitter in recent months, aiming to persuade her to launch investigations into various controversial issues such as child labour in cotton fields, or the Andijan massacre of 2005, when it is believed that Karimov's security forces gunned down hundreds of unarmed protesters.

"Even when she was Uzbekistan's representative to the UN in Geneva, where the international body's human rights council is located, she repeatedly refused to talk about these things," said Stroehlein. "Now that she's fallen out of favour with some part of the regime, now that a few people close to her have allegedly been roughed up by the same forces she backed and spoke for for years – now she's talking about abuses and wants to be taken seriously?"

Karimova admitted she was perhaps blind to the abuses before. "I didn't want to get into conflicts and didn't see many of the things which were disturbing many people, as I was busy working on real people's projects, grants and supporting professional societies. Some people were speaking loudly about it, but it took time to realise the reality we live in."

Karimova has long been seen as a possible successor to her father, though she denied to the Guardian that she had ever wanted the job. "I would like to confirm once again that I never ever stated any 'political or presidential ambitions'. And I should make it very clear again for all those who worry a lot right now."

There are rumours about the health of Karimov, who at 75 is rarely seen in public and does not give interviews. Jockeying for position around Karimov before the 2015 election is the most likely reason for the infighting within the first family.

Karimova said her father was "very upset" but had not taken a side between his two squabbling daughters. "I strongly believe that no father can really be comfortable picking one of two river sides," she wrote. "In my opinion that is a weird thing to ask the guy to do."