The Saudis have "blocked the path to Allah".
With Iranians barred from the annual hajj pilgrimage, thousands protested in Tehran on Friday and officials criticised Saudi Arabia's refusal to discuss last year's deadly stampede.
Around 64,000 Iranians allocated places for the hajj under a quota system will be absent when it starts on Saturday, after talks between the increasingly bitter rivals fell apart earlier this year.
As a war of words grows between the two regional rivals, several thousand people took to the streets of the Iranian capital after the Friday weekly prayers.
The Saudis have "blocked the path to Allah. It's a crime and they must be tried," said Javad Zolfaghari, a cleric who joined the protests.
In an interview with AFP, the head of Iran's Hajj Organisation blamed the Saudis for refusing to discuss security measures despite the stampede that killed thousands during last year's hajj.
"How are you going to invite 1.5 million pilgrims and not even allow yourself to think about the security measures?" asked Said Ohadi.
He said that during negotiations in April and May, the Saudis simply fell back on verses of the Koran holy book stating that anyone who enters Saudi Arabia has "full security".
"Last year we had those verses in the Koran too," said Ohadi.
Iran had the highest confirmed death toll among foreign nationals in the stampede with hundreds of its citizens killed.
An AFP tally found that a total of at least 2,300 people died, but Tehran says the overall toll was much higher.
"Seven thousand people were martyred, were killed, from 39 countries," Ohadi said.
Saudi Arabia says the figure was only 769, but has refused to release the details of its investigation.
Ohadi said the last straw in the hajj talks was a demand from the Saudis that Iranian pilgrims "cannot have any contact with any Muslim from any other country".
That was despite the Koranic verses' emphasis on the importance of mingling with Muslims from around the world during the pilgrimage to Islam's holiest sites in Mecca and Medina, in western Saudi Arabia, he said.
Saudi Arabia has countered that Tehran had made "unacceptable" demands during the talks, including the right to organise demonstrations "that would cause chaos".
But right from the start, Ohadi said there was "very bad hospitality" and "weird attitudes" from the Saudis -- including a refusal to give delegates diplomatic entry, or even cars to their hotel.
Ohadi said depriving the Iranian faithful of the chance to perform the hajj was "unacceptable", especially given the 15-20 year waiting list.
The Saudis "believe they are the owners -- that Mecca and Medina are their properties," he said.
"No -- they are the properties of Islam."