Muslims on the island of Zanzibar are protesting over a police ban on women driving whilst wearing veils.
Police say they want to cut traffic accidents in Zanzibar
Police commander Ramadhan Khatib says the ban, aimed at reducing traffic accidents, takes effect immediately.
But Muslim leaders say it is as an attack on the religion observed by some 95% of the island's population.
Police recorded more than 600 accidents last year, but there are few women drivers on Zanzibar and no indications if any were caused by veiled drivers.
"A survey conducted last year showed that the number of accidents is on the rise within the island and we have to reduce the causes. Veils have the ability to obstruct the sight of the driver and we will not allow them," said Mr Khatib.
But Ali Hazan, leader of the Muslim Awareness Campaign group in Zanzibar, says the police directive is against the teachings of the religion that requires women to wear the veil and they will not accept it.
"We were not consulted over this issue and are concerned that the police, knowing that most people here are Muslims, can issue such a careless directive," he said.
The BBC's Ally Saleh in Zanzibar says police insist that this is not targeted at Muslims.
But the few women drivers on the roads do not support police claims that veils may be harmful, our correspondent says.
"If one has properly fastened her veil it will not distract her," Asha Hamida told the BBC
"The police should check on other causes of accidents like drink-driving and unqualified drivers on our roads, but not target women."