France has called on the Iranian authorities to explain the death in custody of a blogger who, opposition activists say, was killed by torture for criticising the government on the internet.

A French foreign ministry spokesman said on Thursday that Paris was "profoundly shocked" to have learned of the death in custody of 35-year-old Sattar Beheshti.

"We call on the Iranian authorities to shed as much light as possible on the circumstances of his death," the spokesman said.

"The repression of peacefully expressed dissident voices in Iran is unacceptable."

According to opposition groups, Beheshti's family were asked on Wednesday to collect his body from the Kahrizak detention centre in Tehran, where he had been held since being arrested on October 30.

In the last blog he wrote before his arrest, Beheshti had said he was being constantly harassed by telephone by members of the security services.

"Yesterday they threatened to tell my mother that she would soon be wearing black if I did not shut up," he wrote.

It is thought Beheshti was targeted for his writings on political and social issues on his blog and on Facebook.

Beheshti's family say they have been prevented from visiting his grave, with the exception of his brother-in-law.

Amnesty International (AI) has also called on the Iranian authorities to answer questions on Beheshti's death.

"Fears that Sattar Beheshti died as a result of torture in an Iranian detention facility, after apparently lodging a complaint about torture are very plausible, given Iran’s track record when it comes to deaths in custody," said Ann Harrison, AI's deputy Middle East and North Africa programme director.

Source: Agencies