The sentence comes at a time of increased tension between Israel and Iran and speculation of a possible Israeli attack on the Islamic Republic's nuclear installations.
"Ali Ashtari, who had been accused of spying for the Zionist state and charged with engaging in espionage for (Israel's) Mossad intelligence service, has been given the death sentence," the ISNA news agency said.
Iranian media had said Ashtari, 43, was put on trial on Saturday. But an official in Israel's foreign ministry on the same day said Israel was not familiar with the case.
The semi-official Fars News Agency said Ashtari had confessed to the charges against him and asked for clemency.
(Reporting by Hashem Kalantari; Writing by Fredrik Dahl; Editing by Dominic Evans)
