Rioting in the streets of Zanzibar's Stone Town.
Protesters are demanding to know the whereabouts of an Islamic leader - missing since Tuesday.
The Islamic Revival Forum leader Sheikh Farid Hadi is an ardent proponent of Zanzibar's secession from mainland Tanzania.
It was rumoured that police were holding the cleric but they refuted the claims.
The chaos paralysed traffic and business as the missing cleric's supporters rampaged through the streets.
Clashes continued as police tried to disperse the rioters using tear gas.
One police officer was said to have killed by the Islamic protesters while he was on his way home.
The protests were reportedly ongoing.