AP — Iran’s semi-official Fars news agency says a supporter of a Sufi leader has rammed a bus into police, killing three of them before being arrested.

The semi-official ILNA news agency quoted Mohsen Hamedani, a senior security official in Tehran, as saying a gunshot was heard in the area on Monday, without providing further details.

Supporters of Sufi leader Nourali Tabandeh gathered near his residence earlier this month, fearing his arrest despite police assurances that they have no intention of detaining him.

Iran’s clerically-overseen government frowns on Sufism, the mystical strain of Islam, which many conservatives view as a deviation from the faith.