South African mobile operator MTN Group said Monday it was under US investigation over its activities in Iran and Afghanistan, at a time of icy ties between Washington and Pretoria.
Africas biggest telecoms company is already facing court challenges in South Africa by Turkeys Turkcell, which accuses it of winning the Iranian market through corruption.
In 2006, MTN was chosen over Turkcell to become the 49 percent minority shareholder in Iranian government-controlled mobile phone carrier Irancell.