DUBAI (Reuters) - Iranian authorities have confirmed the death of a social media activist jailed on security charges, the semi-official ISNA news agency reported on Sunday, after Western rights groups said he had died following a 60-day hunger strike in prison.

“The political prisoner Vahid Sayyadi Nasiri, on hunger strike since October 13, 2018 to protest the denial of his right to counsel and inhumane prison conditions..., has died at the Shahid Beheshti Hospital in Qom,” the U.S.-based Center for Human Rights in Iran said on its website.

ISNA quoted an unidentified source as saying Nasiri had been jailed twice for belonging to a royalist group and planning acts of sabotage including an explosion. He had been taken from prison to a hospital where he died due to a liver disease on Dec. 12, the source said, without referring to a hunger strike.

Mehdi Kaheh, the prosecutor in the city of Qom, earlier said Nasiri had been serving a sentence for “insulting Islamic sanctities” on social media when he fell ill and was taken to hospital where he died, the state broadcaster IRIB reported on its website. Kaheh did not refer to a hunger strike.

Iran, whose officials often warn of efforts by foreign enemies to infiltrate state institutions, has detained scores of journalists and social media activists in recent years, and many others have gone into exile.

In November, Reporters Without Borders said Iran had launched a new crackdown on journalists in which several had been questioned and three arrested in connection with social network posts.

Iran rejects criticism of its human rights record by international human rights bodies as politically motivated and based on a lack of understanding of Islamic laws.