At least 56 people have been executed in Iran on national security-related charges since March 19, including 27 in cases linked to protests at the start of the year, United Nations human rights chief Volker Turk said on Wednesday.
"I am alarmed by the rise in executions and death sentences issued in Iran since March, and that capital punishment continues to be used to instill fear among the population and suppress dissent," Turk said in a statement.
Iranian authorities killed thousands of people during anti-government protests in January, Iran's worst domestic unrest in decades.
Rights groups say the government has continued to crack down on opponents during the war – sparked by US-Israeli strikes on Iran since the end of February.
Turk said more than 100 people face the risk of execution on similar security-related charges, while executions for drug-related offences were also continuing at an "alarming rate."
He urged Tehran to halt all executions, move towards abolishing the death penalty and raised concerns about what he described as failures to uphold fair trial and due process.
Iran's diplomatic mission in Geneva did not immediately respond to a request for comment.
Iranian officials have defended the country's judicial processes and the use of capital punishment as consistent with domestic law and necessary for public security.
