The development came amid ongoing nationwide protests sparked by the death in custody of Jina Mahsa Amini.
The 22-year-old from Iran’s Kurdistan region was arrested on September 13 by Iran’s so-called “morals police” for not wearing her hijab properly.
Thousands have been arrested across the country for participating in peaceful protests, according to OHCHR.
“At least six people involved in the protests have been sentenced to death on charges of ‘moharebeh,’ or ‘waging war against God,’ or ‘efsad-e fel-arz,’ or ‘corruption on earth,’ spokesman Jeremy Laurence said. . .
“A growing number of people, including Iranian celebrities and sportswomen and men, who have expressed their support for the protests have been subpoenaed or arrested,” he added.
According to OHCHR, security agents reportedly responded “vigorously” to demonstrations at several mostly Kurdish locations on Monday evening, including Javanrud and Saqqez, Ms Amini’s hometown.
Two 16-year-old boys were among the six killed over the weekend, according to the UN rights agency, which noted that more than 300 people, including 40 children, have lost their lives since nationwide protests erupted on Sept. 16.
Families denied bodies of relatives
OHCHR also reiterated its concern that authorities have refused to release the bodies of the dead to their families, or made their release “conditional” by not speaking to the media.
“With regard to bodies not being returned to their families, that is of course a major concern for us,” said Mr. Lawrence.
“I’m not sure what the motive behind that is. But the families have the right to get the bodies of their loved ones back. It’s cruel that they aren’t.”
Mr Laurence noted that the security forces’ approach had hardened on protesters, who have been killed in 25 of Iran’s 31 provinces, including more than 100 in Sistan and Baluchistan.
He urged authorities to meet people’s demands for “equality, dignity and rights” – instead of using disproportionate force against demonstrators.
“The lack of accountability for gross human rights violations in Iran remains persistent and adds to growing grievances,” said the OHCHR spokesperson.
Iranian authorities have also reported that a number of security forces personnel have been killed since the protests began.