Africa: Tanzania threatens to de-register churches who rap president from pulpit

DAR ES SALAAM (Reuters) - Tanzania has threatened to revoke the registration of religious organisations that "mix religion and politics" after a cleric criticised President John Magufuli's leadership in a Christmas sermon.    Opposition leaders in Tanzania say tolerance for dissent has been rapidly disappearing since Magufuli took office in late 2015 with pledges to reform East Africa's third-biggest economy and crack down on large-scale corruption.     Tanzania's constitution protects freedom o