Five Russian scientists who helped Iran with its nuclear weapons programme were among the 45 killed in plane crash in northern Russia last week.
Russia's state atomic energy agency announced that the five - Andrei Tropinov, Sergei Rizhov, Gennadi Benyok, Nicolai Tronov and Valery Lyalin - worked at the Hydropress factory, part of Russia's state nuclear complex.
According to Ha'aretz writer Amir Oren, who spoke to Russian security sources, the five helped build the Bushehr nuclear power plant.
"The experts worked at Iran's Bushehr nuclear power facility after the contract for the plant's construction passed from the German company Siemens to Russian hands in 1995. The five were employed by Hydropress, one of the main companies to work on Bushehr," said Mr Oren.
Russia foreign policy analyst Igor Danchencko, who worked in Iran several years ago, said that the Russian experts have "completed their work there, as far as I understand. Iran could operate the plant on its own from now on if it had enough fuel".
Russia still believes that it was poor weather and pilot error that caused the crash rather than foul play.