In a message relayed by Iranian state media, Ayatollah Ali Khamenei has called on Muslim nations to “fundamentally reconsider the management of the two holy places and the issue of hajj.”

The “two holy places” are the cities of Mecca and Medina, while the hajj is the pilgrimage to visit them, which devout Muslims are supposed to make at least once during their lives. The hajj season begins on September 11.

Reuters notes that Iranian pilgrims will not attend the hajj this year, because talks between Iran and Saudi Arabia broke down in May. The immediate reason for these talks, and Iran’s criticism of the Saudis, was the horrifying stampede that occurred during the 2015 hajj, which killed 769 pilgrims by Saudi Arabia’s count, 131 of them Iranians. (Other sources believe the actual death toll was two or three times higher than Riyadh’s official numbers.)

“Among the suggested causes: pilgrims rushing to complete the rituals, heat, masses of faithful pushing against each other in opposite directions, even confusion among the many first-timers on the annual Islamic pilgrimage to Mecca and Mina,” CNN wrote in September 2015, while the bodies were still being counted.

This was not the first deadly incident to occur during the incredibly crowded pilgrimage, which brings over 2 million visitors to the Muslim holy cities. Critics of Saudi Arabia’s management have long complained about inadequate accommodations, insufficient food and shelter for the throngs of pilgrims, and poor crowd control.

The UK Guardian reports that the Saudis are attempting to address some of these complaints, including increased use of surveillance cameras, more staff with better training, better coordination with hajj missions from other countries, and electronic wristbands for visitors, which will help the authorities monitor crowd movements and detect dangerous buildups.

There is, of course, a political dimension to the dispute between Iran and Saudi Arabia as well, with the two nations conducting a sort of Middle East Cold War that isn’t all that cold, in proxy conflicts like Yemen. The Saudis believe Iran planned to use its hajj pilgrims to stage anti-Saudi demonstrations in Mecca and Medina. Iran has suggested Saudi Arabia deliberately sabotaged the 2015 pilgrimage, or is at best indifferent to the safety of non-Saudi (or non-Sunni Muslim) visitors.

“Riyadh accuses Tehran of destabilizing Arab states and spreading sectarianism by backing militias in Syria, Lebanon, Iraq and Yemen and fomenting unrest in Bahrain and Saudi Arabia. Iran denies those charges,” Reuters writes.

Khamenei brought Iran’s broader conflict with Saudi Arabia into his hajj remarks, urging the Muslim world not to “let those rulers escape responsibility for the crimes they have caused throughout the world of Islam.”

He threw in a dash of anti-Americanism, too, as quoted by the Trend news agency: “Those who have reduced hajj to a religious-tourist trip and have hidden their enmity and malevolence towards the faithful and revolutionary people of Iran under the name of ‘politicizing hajj,’ are themselves small and puny devils who tremble for fear of jeopardizing the interests of the Great Satan, the US.”

“The heartless and murderous Saudis locked up the injured with the dead in containers- instead of providing medical treatment and helping them or at least quenching their thirst. They murdered them,” Khamenei thundered. “Because of these rulers’ oppressive behavior towards God’s guests, the world of Islam must fundamentally reconsider the management of the two holy places and the issue of hajj. Negligence in this regard will confront the Islamic Ummah with more serious problems in the future.”

The BBC adds Khamenei referring to Saudi Arabia’s rulers as “disgraced and misguided people” who have “blocked the proud and faithful Iranian pilgrims’ path to the Beloveds’ House.”