Iran has arrested dozens of people on suspicion of spying as fears grow in the Islamic Republic over the extent of its infiltration by Israel’s Mossad intelligence service.

Israel’s historic strike on Iran revealed years of Mossad activity inside the country, including hidden weapons, drones and assassinations of nuclear officials.

In a statement aired on state television, the Guards said they "struck the military intelligence centre of the Zionist regime's army, Aman, and the Zionist regime's terrorist operations planning centre, the Mossad, in Tel Aviv", adding it was "currently on fire".

Israel and Iran have begun a new round of attacks, as the conflict between the two heavily armed rivals enters its fourth day.

Israel warned hundreds of thousands of people to evacuate the middle of Iran's capital as Israel’s air campaign on Tehran appeared to broaden on the fourth day of an intensifying conflict. An Iranian television anchor fled her studio during a live broadcast as bombs fell on the headquarters of the country's state-run TV station.

TEHRAN: Iranian authorities have executed an individual convicted of spying for Israel’s Mossad intelligence agency, according to state media reports on Monday, as tensions between the two countries

The pre-emptive Israeli strike that reportedly killed nine of Iran’s lead nuclear scientists Friday isn’t the first time Tel Aviv has successfully targeted Tehran’s top experts. Israel launched large-scale airstrikes against Iran on Friday,

For example, due to the strike on Natanz and on other sites, the Islamic Republic has lost much of its centrifuge fleet for enriching uranium, much of its enriched uranium, and at least the presumed lead site for producing uranium metal and hemispheres ti place on a nuclear warhead at Isfahan.