Iran's supreme leader is urging Iranians to avoid all dealings with members of the banned Baha'i sect in a possible prelude to further crackdowns on the minority.
Iran already bans the Baha'i, a religion founded in the 1860s by a Persian nobleman considered a prophet by followers. Muslims consider Muhammad the final prophet.
The fatwa, or religious edict, by Supreme Leader Ayatollah Ali Khamenei is his latest against the group. It supports similar fatwas in the past by other clerics.
An Iranian news website, Tasnim, reported Wednesday that Khamenei called the Baha'i "deviant and misleading."
Baha'i followers are frequently under pressures from Iranian authorities, which has prompted outcry among international human rights groups.
Iran allows non-Muslims such as Christians and Jews to worship, but has strict laws against seeking converts.