Nigeria drags MTN profits down by 20%

South African mobile phone operator MTN Group has warned it will  report at least a 20 percent decline in full-year profit due to weak performance in Nigeria, its biggest market.

MTN said the profit warning did not include a $3.9 billion fine imposed  by Nigerian authorities last year for failing to cut off unregistered SIM card users because it was still in talks with authorities about the final size of the penalty.