Exclusive: Sakineh Mohammadi Ashtiani accuses authorities in Tehran of lying about charges in attempt to execute her in secret

In an exclusive interview with the Guardian, the woman whose sentence of death by stoning triggered an international outcry has accused the Iranian authorities of lying about the charges against her to pave the way to execute her in secret.

Sakineh Mohammadi Ashtiani, 43, was sentenced to death by stoning for adultery but it was commuted to hanging after an international outcry. Her initial sentence was for "having an illicit relationship outside marriage" but Iranian officials have claimed that she was also found guilty of murdering her husband and should still face death by stoning.

In the interview, which took place through an intermediary who cannot be named for security reasons, she said: "They're lying. They are embarrassed by the international attention on my case and they are desperately trying to distract attention and confuse the media so that they can kill me in secret."

Yesterday, Mossadegh Kahnemoui, a senior Iranian judicial official, told the UN's Committee on the Elimination of Racial Discrimination: "This lady, in addition to double adultery, is also found guilty of conspiracy to murder her husband."

Mohammadi Ashtiani said: "I was found guilty of adultery and was acquitted of murder, but the man who actually killed my husband was identified and imprisoned but he is not sentenced to death."

The accused, who has not been named, is not facing execution because Mohammadi Ashtiani's son pardoned him, but she was sentenced to death after a local prosecutor in Tabriz accused her of adultery.

"The answer is quite simple, it's because I'm a woman, it's because they think they can do anything to women in this country. It's because for them adultery is worse than murder – but not all kinds of adultery: an adulterous man might not even be imprisoned but an adulterous women is the end of the world for them. It's because I'm in a country where its women do not have the right to divorce their husbands and are deprived of their basic rights."

Mohammadi Ashtiani also revealed that at the moment the sentence was passed she did not understand the Arabic word used as the legal term for stoning.

"When the judge handed down my sentence, I even didn't realise I'm supposed to be stoned to death because I didn't know what 'rajam' means. They asked me to sign my sentence which I did, then I went back to the prison and my cellmates told me that I was going to be stoned to death and I instantly fainted."

Mohammadi Ashtiani fears that the exile of her original lawyer, Mohammad Mostafaei, has made her more vulnerable. "They wanted to get rid of my lawyer so that they can easily accuse me of whatever they want without having him to speak out. If it was not for his attempts, I would have been stoned to death by now."

Mostafaei volunteered to represent her for free and succeeded in bringing her case to world attention but fled to Turkey when Iranian authorities issued an arrest warrant for him. His wife is being held without charge in Tehran's notorious Evin prison.

Mostafaei, who was arrested on immigration charges in Istanbul, was released today and is on his way to Norway.

Describing life inside Tabriz prison, Mohammadi Ashtiani said she has been subject to constant mistreatment by prison guards. "Their words, the way they see me – an adulterous woman who should be stoned to death – is just like being stoned to death every day."

She thanked campaigners for highlighting her case and said international pressure was her only hope for release. "For all these years, they [the officials] have tried to put something in my mind, to convince me that I'm an adulterous woman, an irresponsible mother, a criminal but with the international support, once again I'm finding myself, my innocent self."

She pleaded: "Don't let them stone me in front of my son."

Twelve women and three men have also been sentenced to death by stoning in Iran.