An international convention has sought to ban the execution of juveniles
A senior judicial figure in Iran has cast doubt on reports that Tehran will stop executing juveniles.
Deputy prosecutor general Hossein Zebhi told a newspaper that under Sharia law only a murder victim's family could commute a death sentence.
He had suggested last week that judges were being told to stop imposing the death penalty on young offenders.
Iran has been widely condemned for being one of the few remaining nations to execute offenders aged under 18.
Amnesty International says at least six youths have been executed in Iran this year alone.
Mr Zebhi was quoted by the daily Etemad-e Melli newspaper as saying: "The principle of retribution... is not up to the government, rather it is up to the private plaintiff."
"Only if the next of kin give their consent can there be a reduction in the punishment," he added.
His earlier comments suggesting a possible ban on juvenile execution had been welcomed by human right campaigners, including Amnesty International.
Critics say Iran's practice of handing down the death penalty to juvenile offenders - those aged under 18 at the time of the crime - is explicitly banned by the International Convention on the Rights of the Child, to which Tehran is a signatory.
Many convicted juvenile offenders have been on death row for years, as negotiations continue over whether victims' families will accept blood money - cash to avoid execution.