Iran said Wednesday it had sentenced a citizen to death for spying for Israel in return for Swedish residency, after rights activists reported an Iranian-born academic was handed the death penalty.

Amnesty International on Monday announced that emergency medicine specialist Ahmadreza Djalali, detained in Iran since April 2016, was found guilty of working with the Israeli government.

Tehran's prosecutor general Abbas Jafari Dolatabadi did not name Djalali but said a suspect was sentenced to death for passing information on Iran's nuclear programme to agents from Israel's Mossad intelligence agency in exchange for a Swedish residency permit.

"One of the actions of the convict was revealing the location of and some information on 30 outstanding individuals engaged in military and nuclear research projects," Jafari Dolatabadi said in comments quoted by the judiciary's Mizan website.

He said the information led to the assassination of two Iranian nuclear scientists, Majid Shahriari and Masoud Alimohammadi, killed in bomb blasts in 2010.

Under Iranian law the identity of a convicted person cannot be released until the appeals process is over.

Amnesty International has slammed the trial of Djalali -- who has studied and taught in Sweden, Italy and Belgium -- as "grossly unfair" and called on the authorities to release him and drop all charges. 

Between 2010 and 2012, five Iranian scientists -- four of them involved in the country's nuclear programme -- were murdered in bomb and gun attacks in Tehran.

The Islamic republic accused the US and Israel of killing its scientists, including Shahriari, a key member of Iran's Atomic Energy Organisation and Mostafa Ahmadi Roshan, a deputy director of the Natanz nuclear enrichment facility.

In 2012, Iran executed Majid Jamali Fashi, convicted for working for Mossad and assassinating Alimohammadi.

Three others, including nuclear scientist Shahram Amiri, have been hanged since for working for Israel and the US.