Iranian general suggests Saudi crown prince could commit regicide
Harsh rhetoric has been common between the two rivals since January but the remarks by Revolutionary Guard General Qassem Soleimani's take things to an entirely different level by discussing Saudi King Salman being killed.
The semi-official Fars and Tasnim news agencies quoted Soleimani making the comments late on Wednesday night at a mourning ceremony for an Iranian general killed in Syria.
Soleimani, head of the paramilitary force's expeditionary Quds force, referred to Saudi Deputy Crown Prince Mohammed bin Salman as being so "impatient," the royal "might kill the king".
Mohammed bin Salman was appointed by his father last year to head the defence ministry, making him the youngest defence minister in the world.
He had been described as the power behind the throne of his father, King Salman.
His first major move as defence minister was the launch of the Saudi-led militarily intervention in neighbouring Yemen in 2015, fighting against Iran-backed Houthi rebels.
In its war on Yemen, the kingdom has been accused of committing human rights violations, according to the UN and rights groups.
Soleimani headed Iran's Quds' Force in Syria, supporting the regime in its fight against Saudi-backed rebel groups.