Saudi Arabia's King Salman urged arch-rival Iran on Wednesday to abandon an expansionist ideology that has "harmed" its own people, following violent street protests in the Islamic republic.
A wave of demonstrations erupted in the sanctions-hit country on Friday after an announcement that petrol prices would be raised by as much as 200 percent with immediate effect.
"We hope the Iranian regime chooses the side of wisdom and realises there is no way to overcome the international position that rejects its practises, without abandoning its expansionist and destructive thinking that has harmed its own people," the king told the consultative Shura Council.
The region's leading Shiite and Sunni powers have no diplomatic ties and are at odds over a range of issues, including the wars in Syria and Yemen.
"The kingdom has suffered from the policies and practises of the Iranian regime and its proxies," King Salman said, quoted by the foreign ministry, reiterating that Riyadh does not seek war but is "ready to defend its people".
Saudi leaders regularly accuse Iran of stirring conflicts by supporting Shiite movements in the region.
Tehran denies the charges and in turn says Riyadh supports radical Islamist groups.
King Salman said he hoped for a political settlement in Yemen, where the Iran-aligned Huthi rebels have been fighting the Saudi-backed government for than four years.
Saudi Arabia and its allies intervened in the conflict in 2015, shortly after the Huthis took over the capital Sanaa.
King Salman said he hoped a recent Saudi-brokered agreement between the Yemeni government and southern separatists would "open the door for wider peace talks" to end the conflict.
Tensions have soared between Riyadh and Tehran after a recent string of assaults on oil tankers and installations in the Gulf.
In the latest attack on September 14, drone strikes targeted two Saudi oil facilities, temporarily knocking out half of the kingdom's oil production.
The attacks were claimed by the Huthis, but Washington and Riyadh said Iran was responsible, and that the strikes were carried out with advanced missiles and drones.
The king's annual address to the Shura Council, which he uses to outline the kingdom's domestic and international policy, was not aired on Saudi state television.
Authorities did not give a reason for the shift from previous years when the speech was broadcast live.
In his speech, the king did not mention a two-year Saudi-led boycott of neighbouring Qatar, amid speculation of an easing of tensions.
Not did he comment on Washington's decision this week to no longer consider Israeli settlements in the occupied West Bank illegal.
However, the foreign ministry in a statement Wednesday said Saudi Arabia completely rejected Washington's stance, the official Saudi Press Agency reported.