A senior Iranian official branded Saudi Arabia's King Salman a traitor to Islam on Thursday and equated the Gulf state's military assault on Iranian-allied fighters in Yemen with Israeli actions against Palestinians.
Alaeddin Boroujerdi, head of Iran's national security and foreign policy committee, speaking in Damascus, also reiterated his country's support for the Syrian government, which is battling an insurgency backed by Saudi Arabia.
Shi'ite Islamist Iran has been a vital ally for Syrian President Bashar al-Assad during the four-year Syrian war, providing crucial military and economic support.
Syria is a focal point in a wider regional struggle between Tehran and Riyadh and which is also playing out in Yemen.
"We are here to announced anew that our support for Syria — government and nation — is solid and continuous, and we are proud of this support," Boroujerdi said, according to a report on the Syrian state news agency SANA.
In fierce rhetoric, Boroujerdi said "God would take revenge" against the Saudi monarch for serving what he called U.S.-Israeli interests in the war against the Shi'ite Houthi rebels.
"He should be called the traitor of the noble Haramayn and the Islamic nation and against all the teachings they are killing children in Yemen with American weapons and replicating the crimes of the Zionist entity," he said.
Saudi Arabia is the birthplace of Islam and home of its holiest sites in Mecca and Medina — referred to in Arabic as the Haramayn.
"They will have to expect heavenly revenge," he said.
His comments in Farsi were translated into Arabic.
An alliance of Gulf Arab nations led by Saudi Arabia has been bombing the Houthi militia and allied army units that control much of Yemen since March 26 in what they say is an attempt to restore exiled President Abd-Rabbu Mansour Hadi.
The United Nations says 828 civilians, including 182 children, have been killed across Yemen in the conflict.
Saudi Arabia and its allies believe the Houthis are a proxy for the influence of their arch-rival Iran in a regional power struggle that has helped exacerbate sectarian tensions across the Middle East.
Riyadh says Iranian support for militias in Lebanon, Syria, Iraq as well as Yemen undermines strong government and boosts Sunni Muslim militants. It accused Tehran of arming the Houthis, charges the Islamic Republic denies.
Israel says its military measures against Palestinians are solely intended to safeguard its own security.