Iran's supreme leader Ayatollah Ali Khamenei demanded Saudi Arabia apologize on Sunday for a stampede that killed nearly
770 pilgrims at the hajj, at least 144 of them Iranians.
"Instead of passing the buck and playing a blame game, the Saudis should accept their responsibility and apologize to the world's Muslims and the bereaved families," Khamenei said in comments reported by the official IRNA news agency.
Iranian leaders have been fiercely critical of Saudi authorities' handling of safety at the hajj and questioned whether Riyadh was fit to continue organizing the annual pilgrimage.
Khamenei's comments came just hours after Saudi Foreign Minister Adel al-Jubeir hit back at the criticism from its regional rival, saying it "shouldn't play politics with a tragedy."
"I would hope Iranian leaders would be more sensible and more thoughtful with regards to those who perished in this tragedy, and wait until we see the results of the investigation," said the Saudi minister.
Culture Minister Ali Janati is to head a delegation to Saudi Arabia to follow up on 323 Iranians Tehran says are missing, but IRNA said his team still has not received visas.
On Saturday, Tehran summoned Saudi Arabia's charge d'affaires for the third time since the stampede, to press the kingdom for greater cooperation.
Iranian President Hassan Rouhani pressed for an investigation of the Saudi hajj stampede, in an address to the United Nations that highlighted Tehran's alarm over the tragedy.
In his speech Rouhani said he wanted to "emphasize the need for swift attention to the injured as well as investigating the causes of this incident and other similar incidents in this years' hajj."
The dispute came amid tensions between Iran and Saudi Arabia over the conflicts in Yemen and Syria that Riyadh views as a bid by Tehran to expand its influence in the region.
Shortly after the stampede tragedy, Iranian Supreme Leader Ayatollah Ali Khamenei blamed the Saudi authorities, citing "improper measures" and "mismanagement".
"The government of Saudi Arabia must accept the huge responsibility for this catastrophe," he said.
And on Friday, Iran demanded that it and other affected countries be represented in the Saudi investigation into the stampede, with First Vice President Eshaq Jahangiri saying "there is no question about the poor management" of the pilgrimage and the "inexperience of security personnel" on the ground at the time.
AFP contributed to this report.