TEHRAN (AFP) - Iran has hanged an Iranian telecoms salesman convicted of spying for arch-enemy Israel, a senior official said on Saturday, warning that a "more serious intelligence war" had begun with the Jewish state. "Ali Ashtari, who spied for the Zionist regime intelligence service (Mossad) was hanged on Monday November 17," the state news agency IRNA said, quoting the intelligence ministry's counter-espionage director, whose name was not given. "He had spied for Mossad for three years," the official said, adding that "his espionage was so evident," that there had never been any hope of a successful appeal against the verdict. Ashtari, 45, had been accused of involvement in a plot run by the Israeli secret services to intercept the communications of Iranian officials working in the military and its contested nuclear programme. He was arrested in February 2007 and sentenced to death by a revolutionary court this past June. "By announcing Ashtari's execution we meant to show new intelligence wars have started with the intelligence services of the enemy and intelligence wars have become more serious," the official said. He added that Iran had also arrested four people allegedly tasked by Mossad to carry out assassinations and equipped with "Zionist regime-made weapons" near the border with Iraqi Kurdistan in western Iran. He said the targets were not officials but that "it was important to us as they were supposed to be assassinated by Mossad." Tension has flared between the two countries since the 2005 election of President Mahmoud Ahmadinejad, who has repeatedly said the Jewish state is doomed to disappear and branded the Holocaust a "myth". Israel, which along with the United States accuses Iran of seeking atomic weapons, has never ruled out a military action to halt Tehran's nuclear drive. Tehran insists its nuclear programme is only aimed at producing electricity and angrily points to Israel's widely believed status as the sole, if undeclared, nuclear weapons power in the Middle East region. Fars news agency quoted the official as saying Ashtari would gather information desired by the Israeli intelligence service in Iran and sought to "infiltrate important and sensitive institutions to implement Mossad needs." "He had contacts with nuclear centres in regard to communications equipment," he said adding that Ashtari "exploited the authority that some centres gave him for the sake of technical and defence consultations." He said Ashtari would offer "treacherous consultation to some security and defence centres" and sought to "trap people targeted by Mossad so that the Zionist regime can contact them in due time." The official said Ashtari had also sought to establish ties with other foreign intelligence services without naming any. According to his confessions in June, Ashtari said Mossad gave him 50,000 dollars to buy Internet cables and satellite phones and then sell them on to "special customers" in the hope of enabling Israel to spy on their communications. He said he met his handlers in Thailand, Turkey and Switzerland and that he was given equipment including a laptop through which he could send encrypted emails. They wanted "me to sell these terminals in Iran to my special customers so they could hack into this equipment," he said. "I am not sure what they intended to do as before I sold these to my customers I was arrested." Trials against Iranians accused of spying for Israel are a rarity, despite the enmity between the two states.