Iranian nuclear scientist Shahram Amiri was executed for passing information to the United States, officials in Tehran confirmed Sunday.
"Amiri forwarded important secret information to our nemisis and Great Satan," judiciary spokesman Hgolam-Hossein Mohseni-Ejei said, according to the country's official IRNA news agency.
He was hanged on Wednesday in Tehran, the spokesman said, confirming earlier reports at the weekend about the 39-year-old's execution.
Amiri had been a controversial figure for some time. Some reports called him a whistleblower who had left Iran for the United States in 2009 and divulged information on Iran's nuclear programme.
Other reports alleged that Amiri had been kidnapped by the CIA in Saudi Arabia, taken to the US and forced to talk.
The United States repeatedly rejected allegations that the nuclear scientist had been held against his will.
Amiri was allowed to return to Iran in 2010, where he was initially celebrated as a national hero.
He was later arrested and sentenced to 10 years in prison for espionage. Officials then accused him of continuing to provide information to the United States and the death penalty was later imposed by the Supreme Court.