Hizb ut Tahrir, a pan-Islamic group banned in several countries, has launched a new campaign in politically volatile Zanzibar, an island off the coast of Tanzania.
The new campaign began when the group put up a series of posters overnight on Monday on the main island of the semi-autonomous Indian Ocean archipelago.
The posters read simply 'The Solution is Khilaffa'. The slogan refers to the group's aim of creating a worldwide caliphate - or Islamic state - led by a single Islamic leader.
"We are part of the international alliance calling and believing that Muslims should be led by one caliphate," Chande Khamis, a member of the group, said in Zanzibar's business district on Tuesday.
al Jazeera