Saudi Arabia and Iran are locked in an ongoing power struggle to be the main power in the region.
The bickering powers are also essentially fighting a proxy war in Yemen, with the Saudis backing the ousted government, and the rebels backed by Iran.
Tehran has now issued a new fiery threat that it will launch 1,000 missiles at the Saudicapital Riyadh.
It said the city of five million people will be levelled if the Middle Eastern kingdom attacks Iran.
Major General Yahya Rahim-Safavi made the fiery threat as he addressed a gathering of Iran’s military on Sunday.
The general warned the royal palaces of the Saudi king and crown prince would be destroyed by Tehran.
He threatened Iran’s perceived enemies and boasted they were the supreme power in the Middle East.
No regional decisions can be made without the involvement of Iran, he said.
And the general boasted there is not a power in the Middle East that can pose a threat to them.
He said: "Saudi Arabia knows it well that if it acts like a fool and invade Iran, the Islamic Republic will fire 1,000 missiles at the Saudis palaces in Riyadh on the first day of the invasion.”
General Rahim-Safavi, a senior military advisor to the Ayatollah, was a former commander in the Iranian Revolutionary Guard.
He blasted the US for losing major allies in the Middle East.
And cryptically he said Iran has “special plans for every scenario”.
Iran and the US have been at loggerheads this year as US President Donald Trump scrapped the nuclear deal with Tehran.
Trump blasted the arrangement that was established to curb Iran’s ambitions of obtaining nukes.
Iran threatened to restart its nuclear programme unless Europe fills the void left by Washington.
The deal had been to suspend US sanctions on Iran in exchange for the surrender of its nuclear programme.
Iran and Israel are also at each other’s throats over Tehran’s build-up in Syria – which Iran warned will be "another Vietnam" for the US.
The Ayatollah’s troops have been described as leading the ground war against the Syrian rebels for Bashar al-Assad.
Jerusalem has accused Tehran of trying to establish military bases in the war-torn country with the eye of later attacking Israel.
General Rahim-Safavi said: "The Zionists have already lost most of their power in the region.
"If the regime had enough power, it would remove Syrian President from power.”
