Iran’s Supreme Leader has capped weeks of escalating rhetorical challenges to Saudi Arabia, proclaiming on Saturday that Riyadh’s leaders are not good Muslims.

Echoing statements made earlier this year by other senior Iranian clerics, Ayatollah Khamenei told his audience that
Saudi rulers believe in the Qur’an only in appearance as they act in contravention of its teachings: “Unfortunately today, the Islamic society, like other societies, has faced problems and the fate of some Islamic societies is in the hands of incompetent individuals like [those] in the Saudi government.”

He singled out the Saudi military intervention in Yemen’s civil war and its support of repression by Bahrain’s monarchy, insisting that those carrying out “illegitimate” operations will face failure and doom. He asserted that “if the Muslim world acts correctly, [Saudi leaders’] collapse will be accelerated”.

Relations between Saudi Arabia and Iran have long been tense in the region, with Riyadh breaking off diplomatic links in January 2016 after the Saudi execution of a prominent Shia cleric and an attack by a Tehran crowd burning the Saudi Embassy.

In the past month, there has been further deterioration after the Saudi Deputy Crown Prince and Defense Minister Mohammad bin Salman said that any battles will take place within Iran’s borders. Tehran has been further unsettled by Donald Trump’s visit to the kingdom last weekend, with the US pledging $110 billion in arms sales — and $380 billion over 10 years — to the Saudis and dozens of regional leaders attending a “Riyadh Summit” in which criticism of Iran was prominent.

On Saturday, Khamenei dismissed attempts by brokers, including Gulf states such as Kuwait and Oman, seeking an easing of the tension between Iran and Saudi Arabia. Referring again to Riyadh, he said some reactionary countries falsely assume that they can establish cordial relationship with enemies of Islam but “the fact is that there is no intimacy”.

The speech was also a further caution to President Rouhani following his re-election last weekend — the President has advocated a foreign policy of “engagement”, including with a rival like Saudi Arabia, rather than confrontation.