Three policemen were killed in “a vicious attack” in the Iranian capital during protests by a Sufi sect on Monday, a police spokesman told local media.
“Three police officers were martyred in the street in a vicious attack using a bus,” spokesman Saeed Montazer Almehdi told the official IRNA news agency.
Unverified footage circulating on social media appeared to show the moment the bus ploughed into a group of police officers in northern Tehran.
Members of Iran’s Gonabadi Sufi order, known as dervishes, were protesting the arrest of members of the sect, according to unconfirmed social media reports.
Police said gunshots were fired to disperse the protests.
“The law enforcement forces arrested a number of dervishes and ended the protest by firing tear gas,” Mohsen Hamedani, deputy governor of Tehran, told IRNA.
The Gonabadis are one of the country’s largest Sufi sects, originating from Khorasan Razavi province in the country’s northeast but with bases in cities across Iran.
There were unconfirmed reports in late January and early February that security forces had clashed with sect members outside the home of their leader, Noor Ali Tabandeh, in Pasdaran in northern Tehran.
A website linked to the group said police were trying to set up checkpoints around the home to monitor visitors.
Sufi worship is not illegal in Iran but the practice is frowned upon by many conservative clerics.
Officials and the media routinely refer to them as “deceived elements”.
The Islamic mysticism followed by an array of Sufi orders since the early centuries of the faith has always aroused suspicion among orthodox Muslims, whether Shiite or Sunni.
In Shiite Islam, some Sufi orders have been further tarnished by the accusation of heresy because of their association with the unorthodox Alevi faith practised in parts of Syria and Turkey.
Foreign rights organisations have accused Iran of persecuting the Gonabadi Sufis over the years, particularly during the presidency of hardliner Mahmoud Ahmadinejad from 2005 to 2013.