The country’s hardline Revolutionary Guards issued a chilling warning to the ruling Al Saud family saying they will topple the “pro-terrorist, anti-Islamic regime”.
The website of Iran’s Supreme Leader Ayatollah Ali Khamenei also compared Saudi to notorious Islamic State executioner Jihadi John.
It comes after the Sunni kingdom executed Sheikh Nimr al-Nimr and three other Shi’ites along with dozens of al Qaeda members.
The move appeared to end any hopes that the common enemy of ISIS could lead to rapprochement between the two countries.
Nimr was considered a terrorist by Riyadh but hailed in Iran as a champion of the rights of Saudi Arabia’s marginalised Shia Muslim minority.
Outraged Iranian protesters stormed the Saudi Embassy in Tehran early on Sunday morning leaving a trail of destruction
One photograph posted on Twitter showed a baying mob outside the embassy with small fires burning inside.
Another showed a room inside the building with smashed furniture strewn across the floor.