Ali Reza Jamshidi told The Associated Press that Ali Ashtari was hanged on Nov. 17 after being sentenced to death on June 30 by a revolutionary court in Tehran. It was the country's first known conviction for espionage linked to Israel in almost a decade.
IRNA, Iran's official news agency has confirmed the report.
Jamshidi said Ashtari was found guilty of relaying sensitive information on military, defense and research centers which the 45-year-old electronics salesmen worked with, to Israeli intelligence officers.
Iranian officials have said the material that Ashtari allegedly passed to Israel included information on Iran's Atomic Energy Organization.
A top Iranian intelligence official said that the announcement of Ashtari's hanging was part of an "intelligence battle" with the secret agencies of Iran's enemies, the official IRNA news agency reported.
"We had specific intentions with announcing the execution of Ashtari ... we want to show that new intelligence battles with enemy's intelligence services have begun and that intelligence battles have become more serious," IRNA quoted the head of Counterespionage Department at the Intelligence Ministry as saying.
The news agency didn't identify the intelligence official by name, which is customary in Iran.
The semi-official Mehr news agency quoted the same official as saying Saturday that Ashtari's body was handed over to his family last Monday and later buried.
Jamshidi, the spokesman, said Ashtari was arrested in 2007 after cooperating with the Israeli foreign intelligence agency Mossad for three years. Prior to his trial, Iranian officials accused Ashtari of trying to "create a link" between Iranian experts and Israeli agents.
Iran and Israel have long been enemies. But the ruling against Ashtari is the first time since 2000 that an Iranian court has convicted an Iranian citizen of charges of espionage for Israel. The ruling against Ashtari was handed down by Iran's Revolutionary Court, which handles security issues.
A closed-door trial in 2000 convicted 10 Iranian Jews of spying for Israel and sentenced them to prison terms ranging from four to 13 years. All were released before serving out their full sentences.
Ashtari's hanging comes amid rumors of Israeli intentions to attack Iran's nuclear facilities because of charges that Iran is seeking to build nuclear weapons.
Israel, the United States and many Western countries contend that Iran's nuclear program is intended to produce nuclear weapons. Iran denies that, saying its program is for peaceful purposes.
Earlier this year, Israel Aerospace Industries unveiled its Eitam airplane, equipped with sophisticated intelligence-gathering systems.
Israel also launched an advanced spy satellite in January able to track events even at night and in cloudy weather - all of which could be used to spy on Iran.
In 1981, an Israeli air attack destroyed an unfinished nuclear reactor in Iraq. Israel also hit a suspected nuclear facility in Syria September 2007.