Iran could postpone the death sentence of Iranian-Swedish academic Ahmadreza Djalali, which had been widely expected this week, after an appeal by his lawyers, its Foreign Ministry said on Monday.
Iranian media said Mr Djalali was due to be executed by May 21 for allegedly passing information to Israel but the judiciary is considering a delay, ministry spokesman Saeed Khatibzadeh said.
Mr Djalali’s family and supporters held demonstrations on Saturday to call for his release. His 10-year-old son took part, carrying a placard that read: “Free My Dad”.
Mr Djalali was arrested in April 2016 and convicted the following year of passing information to Israel's Mossad spy agency about two Iranian nuclear scientists that led to their assassinations. He was sentenced to death.
But the United Nations said he should be freed and receive compensation, after an unfair trial using a confession obtained through torture.
"Mr Djalali's sentence is definite, as the judiciary had announced," said Mr Khatibzadeh. "They [his lawyers] have requested that the execution be done at another time.
"It is being considered ... the judiciary will naturally follow up on the case."
UN envoy Enrique Mora called for his release last week on humanitarian grounds as he visited the country to help revive the 2015 nuclear pact.
"I want to underline that in Tehran I raised the need to stop the execution of #AhmadrezaDjalali and asked for his release on humanitarian grounds," Mr Mora tweeted after the two-day visit which ended on Friday.
Mr Djalali, who had lived in Stockholm and worked at the Karolinska Medical Institute, received Swedish citizenship while in detention in February 2018.
The latest threat of imminent execution coincided with the end of a trial in Sweden of Hamid Nouri, a former Iranian regime official who is accused of involvement in the state-backed killing of thousands of opposition activists in Iranian prisons in 1988. A verdict is expected in July.
Iran had previously threatened to execute Mr Djalali in 2020, as a Belgian court was considering verdicts in the case of Assadollah Assadi, an Iranian spymaster, who was accused of plotting to blow up a dissidents’ rally in France. The threat of immediate execution was lifted, even after Assadi was convicted and jailed for 20 years.