Many Tanzanians were surprised to hear in May this year that there was rioting in usually-peaceful Zanzibar. Supporters of an Islamic group named Uamsho, that calls for the islands of Zanzibar to secede from the union with mainland Tanganyika, demonstrated against the union and clashed with police. Two churches were burned in the unrest, although Uamsho denies its supporters were involved.
Zanzibar and Tanganyika formed the union, and together became Tanzania, in 1964. The union has not faced many major challenges until recently. In April Tanzanian President Jakaya Kikwete told constitutional review commissioners at their swearing-in ceremony that they should not entertain any talk of Zanzibar seceding, as this year's constitutional review proceeds. Zanzibaris who want a referendum on the issue were angered, and the secession movement seems to have gathered momentum since.
Uamsho appears to enjoy a solid support base among the islands' majority-Muslim population. The Christian minority, many of them originating from the mainland, are anxious.
The central union government has been criticised by some for not reacting quickly enough, for initially not condemning Uamsho, and for not addressing the underlying grievances that fuel the demand for secession. Many in both Zanzibar and Tanganyika are poor and feel they are marginalised by corrupt politicians. However, this is common across the whole region, and while many see secession as a possible solution, it is not abundantly clear how it would help, and what tangible benefits it would bring.
Meanwhile the main opposition party, the Civic United Front (CUF), is also calling for secession, but with a secular government. Some believe the party is connected to Uamsho, although it denies any link.
CUF's Deputy Secretary Ismail Jusa Ladu told us that Zanzibar, with about one million inhabitants, should be governed separately because its tourism-based economy is different to that of the mainland. Tanganyika, with a population of about 40 million, also has tourism but the economy is dominated more by natural resources and some industry.
Some observers believe the discoveries of offshore oil in both Zanzibari and Tanganyikan waters play a role. Uamsho critics say the group is using the appeal of religion and sovereignty to rally support for secession, but with an eye to controlling natural resource wealth. Many believe the group has financial backing from proponents of political Islam in the Gulf, although when we spoke to one of Uamsho's leaders, Mselem Ali Mselem, he denied it - he told us the group has no foreign support.
In the coming months and years we will see if the pro-secession movement develops, and if the union holds up or Zanzibar wins a greater degree of sovereignty - with either Islamic or secular government. Secession may or may not solve the problems faced by many Zanzibaris, and it could create new problems, too. However, without a concerted effort from the union government and union proponents to win back some Zanzibari hearts and minds, talk of secession is unlikely to go away anytime soon.>
CUF's Deputy Secretary Ismail Jusa Ladu talks to Al Jazeera