Several others were injured when rival groups of Muslims held running battles with armed riot police around a mosque.

The BBC's Dar es Salaam reporter Christine Otieno says the two groups had been at loggerheads over use of the Mwembechai mosque for a service to commemorate two Muslims who died in religious riots in 1998.

Dar es Salaam regional police commander Alfred Tibaigana confirmed two deaths to reporters, but witnesses said three people had died.

Riot police surrounded the mosque early on Wednesday afternoon to prevent what they termed a possibly volatile situation.

But violence flared after members of the so-called Ponda group gathered in the area with the intention of holding special prayers without the permission of the group currently occupying the mosque.

Correspondents say police with batons arrested and beat scores of Muslims and used teargas in an attempt to disperse the crowd.

Police sealed off the area, saying they expected to spend the night outside the mosque to ensure that demonstrators did not return.

Witnesses say there were about 40 arrests.

Religious strife

The conflict between the two groups dates back to religious riots between the authorities and the local Muslim community in 1998.