Eight Iranians convicted of theft are at imminent risk of having their fingers cut off, campaign groups warned on Friday.

The eight men are being held in Greater Tehran prison awaiting the amputation of their fingers on one hand, the Abdorrahman Boroumand Center for Human Rights in Iran (ABC) and Amnesty International said in separate statements.

Three of them had been transferred from Orumiyeh prison in northwestern Iran in May specifically for amputation, AFP said.

According to Amnesty International, the authorities have informed the men that they will be transferred to another prison in the coming days to have their sentence carried out using a guillotine.

All eight were convicted of robbery and sentenced to have their fingers amputated, with the verdict upheld by the Supreme Court, Amnesty said.

On June 8, all eight were called up for transfer for the amputation which was postponed for unknown reasons.

In a joint statement with the Kurdistan Human Rights Network (KHRN), the ABC said it was concerned about ‘credible reports’ that the device had now been installed in a clinic in the prison. Evin in Tehran and has reportedly already been used for at least one amputation in recent days.

“The execution of such cruel and inhumane punishment violates minimum standards of humanity and decency,” said Roya Boroumand, ABC’s executive director.

“The international community can and must respond urgently to stop the implementation of these amputations,” she added.

The ABC said it had collected reports of at least 356 amputation sentences handed down since Iran’s 1979 revolution, but added that the true number is thought to be much higher.