Revolutionary Guard Maj. Gen. Qasem Soleimani attends an annual rally in February commemorating the anniversary of the 1979 Islamic revolution in Tehran. (Ebrahim Noroozi/AP)

The war of words between regional nemeses Iran and Saudi Arabia keeps rumbling on.

Much to the ire of Tehran, the Saudi military conducted live-fire naval exercises in the Persian Gulf, which borders the two countries, and along the Strait of Hormuz. A statement from the Iranian Revolutionary Guard naval forces said that "this war game is mainly to create tension and destabilize the Persian Gulf" and warned Saudi vessels against straying into Iranian territorial waters.

The Saudis countered that the operation, known as Gulf Shield 1, was aimed at improving combat readiness and protecting "the marine interests of the Kingdom of Saudi Arabia against any possible aggression." The subtext, as ever with these two Middle East rivals, is clear.

But then Maj. Gen. Qasem Soleimani waded into the rhetorical battle. Soleimani is the shadowy commander of the Revolutionary Guard Corps' elite Quds Force, a special forces unit that engages in Iran's proxy wars elsewhere.

At a mourning ceremony on Wednesday for an Iranian officer killed in Syria — where Saudi and Iranian proxies are on opposite ends of a conflict — Soleimani reportedly singled out Saudi Arabia's deputy crown prince, Mohammed bin Salman, the youthful, ambitious son of King Salman bin Abdul Aziz who many assume is the heir apparent.

Soleimani claimed that the prince "is very impatient and might kill his king" and suggested that the Saudis are backing rebel factions in Syria only to undermine Iran's influence. The Syrian regime of President Bashar al-Assad is a long-standing Tehran ally.

There's no evidence to suggest that such a provocative allegation is true, though Mohammed bin Salman's ascension has been surrounded by a great deal of palace intrigue, including the grumbling protestations of royals angry about the prince skipping the lines of succession.

Tensions between the Middle East's leading Shiite and Sunni powers have deepened since the young prince's rise, with experts suggesting that he is championing a more aggressive policy toward Iran. Formal diplomatic ties were severed earlier this year after Iranian protesters attacked Saudi offices in the country, following the January execution of a leading Shiite cleric in Saudi Arabia. Iranian pilgrims were officially barred by Saudi Arabia from attending the recent annual pilgrimage to Mecca. Leading religious figures on both sides accused the other of betraying Islam.

Iran's foreign minister even published an op-ed in the New York Times, singling out Saudi Arabia as the incubator of the dangerous ideologies that animate fundamentalist Sunni terrorist groups like al-Qaeda and the Islamic State.

The Saudis, meanwhile, combat Iranian proxies in a range of conflicts through the region, which has led to their protracted involvement in a disastrous war in Yemen. The Iranians also accuse the Saudis of fomenting trouble and see Riyadh's hand behind the resumption of a Kurdish insurgency in Iran's northwest.

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