UN human rights experts have said they are appalled by a "dramatic escalation" in the number of executions in Iran, with more than 1,000 people killed during the first nine months of 2025.

"The sheer scale of executions in Iran is staggering and represents a grave violation of the right to life," the five special rapporteurs warned in a joint statement.

They noted that half of the known executions were for drug-related offences and that nine hangings per day on average had been documented in recent weeks.

There was no immediate comment from Iran. But the government has previously defended its use of the death penalty, saying it is limited to only "the most severe crimes".

It comes on the same day as Iran said a man accused of spying for Israel had been executed.

The judiciary's Mizan news agency named him as Bahman Choubi Asl and reported that he was a database expert who worked on "sensitive telecommunications projects" and was a "trusted spy" of Israel's Mossad intelligence agency, without providing any evidence.

He was hanged on Monday after the Supreme Court rejected his appeal against his conviction on the charge of "corruption on Earth", it added.

Mizan did not say when Asl was arrested, and his case had not previously been reported by Iranian media or human rights groups.

He was the 11th man convicted of spying for Israel to be executed by Iran this year, with 10 of the executions carried out since the 12-day war between the two countries in June.

Last week, Amnesty International and the Norway-based group Iran Human Rights said they had documented the executions of 1,000 people in Iran since January - already surpassing last year's reported total of 975.

According to Iran Human Rights, 50% of those executed this year were accused of drug-related charges; 43% of murder; 3% of the security-related charges of "armed rebellion against the state", "corruption on Earth" and "enmity against God"; and 1% of spying.

They included 28 women, 58 Afghan nationals and what Amnesty described as a disproportionate number of people from minority communities.

Both groups said the executions followed routinely unfair trials that were marred by allegations of torture and other ill-treatment.

"Iran appears to be conducting executions at an industrial scale that defies all accepted standards of human rights protection," the UN special rapporteurs on human rights in Iran, arbitrary executions, minority issues, torture and other cruel punishment, and human rights in Afghanistan, warned on Monday.

The hanging of 499 people for drug-related offences was "particularly alarming", they added.

Between 24 and 30 such executions were recorded per year from 2018 to 2020, following an amendment to Iran's Law on Combating Illicit Drugs. However, the experts said the number has surged since 2021, with a total of 503 reported last year.

International law restricts capital punishment to only the "most serious crimes". "Drug offences do not meet this threshold," the experts warned.

Iran Human Rights reported on Sunday that more than 500 people convicted of drug-related offences were currently on death row at Ghezel Hesar prison in Karaj alone, and that their sentences were all at the "implementation stage".

Iran's powerful constitutional watchdog the Guardian Council is also currently reviewing a draft espionage bill that redefines "collaboration with hostile states", which is punishable by the death penalty, to include acts such as online communication, collaborating with foreign media, and so-called "ideological alignment", according to the UN human rights office.

The UN experts said the international community could not "remain silent in the face of such systemic violations" and that states "must take concrete diplomatic action to pressure Iran to halt this execution spree".