Iran hanged 11 on drugs charges within a 48-hour period, Norway-based Iran Human Rights (IHR) said Wednesday.
They were hanged between the early morning on Sunday and early Tuesday, it noted.
The group added that it recorded a total of 61 executions across Iran in July as Iran presses ahead with a surge in capital punishment that has now seen the country put to death 423 people this year.
Campaigners accuse Iran of using capital punishment as an instrument to spread fear throughout the population in the wake of the protest movement that erupted last September over the death of Mahsa Amini, 22. The Iranian-Kurdish woman had been detained for allegedly flouting the Islamic republic's strict dress rules for women.
Eight men were executed on drugs charges in the main prison of Zahedan between July 30 and August 1, it said.
Another man was executed on similar charges on July 31 at a prison in Birjand city in the eastern province of Khorosan, it added.
Mohammad Arbab, 30, and 32-year-old Asadollah Amini, two Afghan nationals, were secretly executed in Zabol Prison in Sistan-Baluchistan on 30 and 31 July, it said, AFP reported.
The number of executions in Iran on drug-related charges dropped dramatically in 2018 following amendments to the anti-narcotics law but has surged again since 2021.
Rights groups say the demonstrations were targets of deadly crackdowns by the security forces in Iran's poorest region.