The slur was the latest insult in a sharply escalating the war of words between the arch-rivals who back rival sides in political crises throughout the strife-torn region.
Crown Prince Mohammed bin Salman, who is also Saudi defence minister suggested the Islamic Republic’s alleged expansion under Ayatollah Ali Khamenei needed to be confronted.
He told the New York Times: “We learned from Europe that appeasement doesn’t work.
“We don’t want the new Hitler in Iran to repeat what happened in Europe in the Middle East.”
Tensions soared earlier this month when Lebanon’s Saudi-backed Prime Minister Saad Hariri resigned in a television broadcast from Riyadh, citing the influence of Iran-backed Hezbollah in Lebanon and risks to his life.
Hezbollah called the move an act of war engineered by the Saudi authorities, an accusation they denied.
Saudi Arabia has launched thousands of air strikes in a brutal two-year war in neighbouring Yemen to defeat the Iranian-aligned Houthi movement that seized large parts of the country.
The Houthis still retain the main population centres despite the war effort by a Saudi-led military coalition which receives intelligence and refuelling for its warplanes by the US.
More than 10,000 people have died in the conflict.
The group launched a ballistic missile toward Riyadh’s main airport on November 4, which Saudi Arabis decried as an act of war by Tehran.
Prince bin Salman said in May that the kingdom would make sure any future struggle between the two countries “is waged in Iran”.
For his part, Ayatollah Khamenei has referred to the House of Saud as an “accursed tree” and Iranian officials have accused the kingdom of spreading terrorism.