Israel's shadowy intelligence agency Mossad threatened Iranian generals and their families with imminent assassination if they did not quit the Ayatollah's regime, it has been revealed.

The country launched its first wave of strikes on Iran on June 13, targeting military leaders and top nuclear scientists.

And in the hours after the first wave, intelligence operatives from Mossad began a covert campaign to intimidate and destabilise Tehran's regime by calling them on their personal mobile phones.

The Washington Post reported that Persian-speaking Mossad agents called over 20 senior officials in Tehran and told them they'd be killed if they did not renounce the rule of Ayatollah Ali Khamenei, Iran's supreme leader.

One Israeli operative reportedly told a senior general: 'I can advise you now, you have 12 hours to escape with your wife and child. Otherwise, you're on our list right now.'