Tehran will not send its citizens to Saudi Arabia this year to perform Hajj, the Muslim pilgrimage to Mecca, Iran's Culture Minister says.
At last year's Hajj, hundreds of pilgrims were killed - many of them Iranians - in a deadly stampede which Tehran blamed on Saudi officials.
Iran and Saudi Arabia have failed to resolve a row over the pilgrimage with Iranian Culture Minister Ali Jannati blaming "obstacles raised by the Saudis" and Saudi Arabia blaming "unacceptable" Iranian conditions.
But the rivals are split on many other issues, with relations cut in January.
Islam requires devout Muslims to perform the Hajj pilgrimage at least once if they are able, and about 60,000 Iranians attended last year.
Mr Jannati said that "after two series of negotiations without any results because of obstacles raised by the Saudis, Iranian pilgrims will unfortunately not be able to take part in the Hajj" in September.
The Iranian Hajj Organisation said: "Saudi Arabia is opposing the absolute right of Iranians to go on the Hajj and is blocking the path leading to Allah".
It blamed the Saudis for failing to meet Iranian demands for "the security and respect" of Iranian pilgrims.
Visa issues and flights to Saudi Arabia were thought to be key problems.
The Saudi Hajj ministry insisted it had offered "many solutions" to Iran's demands during two days of talks that ended on Friday.
The Saudi foreign ministry said Iran's Hajj conditions were "unacceptable".
In January, Saudi Arabia broke off diplomatic ties with Iran, amid a row over the Saudi execution of a prominent Shia Muslim cleric.
The Saudis executed Sheikh Nimr al-Nimr and 46 others after they were convicted of terror-related offences.
In response, Iranian protesters stormed the Saudi embassy in Tehran, and set fire to the building.
Shia-dominated Iran and predominately Sunni Saudi Arabia are long-standing regional rivals who back opposing sides in the conflicts in Syrian and Yemen.