Iran's judiciary has executed three men for sodomy in a case that sheds new light on the official persecution of gay men and women in the authoritarian Islamic Republic, which has claimed that homosexuality does not exist.

This picture, taken on July 18, 2005, shows Iranian Ayaz Marhoni, 18,
 prior to his execution along with Mahmud Asgari, 16, in the northeastern
city of Mashhad. The two teenagers, convicted of raping a young boy,
said before their executions that they were not aware that homosexual
acts were punishable by death. pic/ AFP photo

According to a report in the Iranian Student News Agency, the men were put to death by hanging on Sunday at Karoun prison in the south western city of Ahvaz. The agency cited Abdolhamid Amanat, an official at the prosecutor's office in Khuzestan Province.

In an unusual announcement, the prosecutor's office said three men had been sentenced for "lavat", the phrase used in Islamic law for sodomy. Only their initials -- MT, TT and MCh -- were given. The statement is at odds with the insistence by Mahmoud Ahmadinejad, the Iranian president, that homosexuality does not exist inside Iran. In 2007 he famously dodged a question from American students during a visit to Colombia University by saying: "In Iran we don't have homosexuals like in your country. In Iran we do not have this phenomenon. I don't know who has told you that we have it."

Human rights groups have said the case is significant because gay men who come before the courts are usually charged with acts such as sexual assault and rape -- crimes that convey an element of coercion rather than consent.

The Ahvaz executions, however, specifically refer to sections 108 and 110 of the Iranian penal code. Section 108 defines sodomy under Iran's interpretation of Sharia law and Section 110 rules that the punishment for lavat is death. Previous executions of gay men have been legitimised by quoting sections of the Iranian penal code that refer to "lavat leh onf" --  sodomy by coercion.

Mahmood Amiry-Moghaddam, a researcher at Iran Human Rights, said: "This case is the only one in recent years where the only basis for the death sentence has been a sexual relationship between two men, with reference to the articles 108 and 110 of the Islamic Penal Code. These articles are very clear."

Confirming executions of gay men and women inside Iran is notoriously difficult. Prosecutors often give few details about the killings, and because of the cultural stigma attached to homosexuality, few families are willing to state publicly whether their loved ones were executed for their sexual behaviour.

In 2005 Iran was widely condemned for executing two teenagers, Mahmoud Asgari and Ayaz Marhoni, who were publicly hanged from a crane in a square at the centre of the city of Mashad. Gay rights groups claimed that the pair were murdered by the state for consensual sex but the charges against them were actually described as "lavat beh onf" against a 13-year-old boy.

Although a number of human rights groups disagreed with gay rights groups over why the two boys were executed, they nonetheless condemned the killings as a breach of the UN Convention on the Rights of the Child and the International Covenant on Civil and Political Rights, both of which Iran is a signatory to.

The country has one of the highest execution rates in the world and has so far put more than 180 people to death this year. The province of Khuzestan, where ethnic Arabs are often persecuted by the authorities, has a particularly high rate of killings. Three other men were put to death in Ahvaz last Sunday, two for robbery and rape and one for drug trafficking.