Iran has urged the Muslim world to unite and punish Saudi Arabia as the bitter war of words between the two countries escalates ahead of the annual Hajj pilgrimage.

On Monday, Iranian Supreme Leader Ayatollah Ali Khamenei criticised Saudi Arabia over how it runs Hajj after a stampede last year killed more than 750 people.

He said Saudi authorities had "murdered" some of them, describing Saudi rulers as godless and irreligious.

Hajj in 360 degrees

"This incident proves once again that this cursed, evil family does not deserve to manage the holy sites," Khamenei said.

In response, Saudi Arabia's Grand Mufti Sheikh Abdulaziz al-Sheikh said he was not surprised at Khamenei's comments.

"We have to understand that they [Iran's leaders] are not Muslims," he told the Makkah daily. "They are children of the Magi and their hostility towards Muslims is ancient."

Magi refers to Zoroastrians and those who worship fire. Predating Christianity and Islam, Zoroastrianism was the dominant religion in Persia before the Muslim conquest.

Custodian of Islam's holiest sites in Mecca and Medina, Saudi Arabia organises the annual Hajj, one of the five pillars of Islam which every able-bodied Muslim who can afford to is obliged to undertake at least once in a lifetime.

Millions of Muslims from around the world have already arrived in Saudi for this year's pilgrimage, which culminates on Sunday.

Relations between Iran and Saudi Arabia hit a new low after the two countries failed to reach a deal on arrangements for Iranian citizens to attend this year's pilgrimage.

At the leadership level, Saudi Arabia and Iran follow different branches of Islam - Sunni and Shia.

Iran boycotted the Hajj for three years between 1988 and 1990 after clashes between Iranian pilgrims and Saudi police in 1987 left around 400 people dead.

READ MORE: Saudi Arabia, Iran trade blame over failed Hajj talks

Diplomatic ties were restored in 1991, but relations have deteriorated in recent years, particularly over the countries' support for opposing sides in the Syria and Yemen wars.

In January, relations were severed again after Iranian demonstrators  torched Saudi Arabia's embassy and a consulate following Saudi Arabia's execution of a prominent Shia leader along with 47 "terrorists".

"If the existing problems with the Saudi government were merely the issue of the Hajj ... maybe it would have been possible to find a way to resolve it," said Iran's President Hassan Rouhani at a cabinet meeting.

"Unfortunately, this government - by committing crimes in the region and supporting terrorism - in fact shed the blood of Muslims in Iraq, Syria and Yemen," Rouhani added.

On Monday night, Iran's Foreign Minister Mohammad Javad Zarif joined the fray on Twitter.

Meanwhile, the head of the six-nation Gulf Cooperation Council hit back on Wednesday, calling Khamenei's remarks "inappropriate and offensive ... and a desperate attempt to politicise" the Hajj.

Khaled Batarfi, senior columnist with the Saudi Gazette, told Al Jazeera that the rebuke to Saudi Arabia over last year's tragedy contrasted with the remarks of Iran's health minister, who said during a visit to the country at the time of the accident that Saudi authorities had provided all needed medical assistance and care to victims of the crush, including Iranian pilgrims.

Saudi Arabia vs Iran: Beyond the Sunni-Shia narrative

Source: Al Jazeera News And Agencies