Turkish operator Turkcell lodged a $4.2 billion lawsuit in South Africa accusing MTN of “corruption and bribery” that caused it to lose business in Iran, according to Reuters.

Turkcell claimed MTN, its former CEO and chairman Phuthuma Nhleko and former executive Irene Charnley “acted wrongfully” and interfered with Turkcell’s relationship with the Iranian government.

In papers filed with the South Gauteng High Court in Johannesburg, and seen by Reuters, Turkcell said MTN’s interference included “promises of bribes and the bestowing of gifts and favours to Iranian and South African Government officials”.

The Turkish operator group also alleged that MTN promised to influence the South African government on a vote in the International Atomic Energy Agency regarding Iran’s nuclear programme.

MTN told Reuters in a statement: “Although we don’t have details of the case, MTN continues to believe that there is no legal merit to Turkcell’s claim and will accordingly oppose it.”

Turkcell filed a similar suit in the US in April 2012 alleging MTN used bribery and wrongful influence to win a mobile licence in Iran that was first awarded to the Turkish operator.

However, the case was dropped in May of that year after the US Supreme Court ruled on an unrelated case that it did not have jurisdiction when two foreign firms were disputing something that took place outside the US.

The South African company rejected Turkcell’s allegations and initiated an investigation that found them to be untrue in February 2013.