JOHANNESBURG (Reuters) – MTN Group Ltd said on Tuesday the chief executive officers of its Zambian and Cote d’Ivoire units would step down at the end of the month.

Africa’s largest mobile phone operator said Zambia’s Philip van Dalsen, who joined MTN in 2012 as CEO of MTN Cyprus, would be replaced by MTN Rwanda CEO Bart Hofker, in October.

Mitwa Kaemba Ng’ambi has been appointed as the new CEO of MTN Rwanda.

The firm said Freddy Tchala, its Cote d’Ivoire CEO, who had a 17-year stint at the firm, would also be leaving at the end of September with his replacement still to be announced.

Spokeswoman Karen Byamugisha said van Dalsen and Tchala are both stepping down due to personal reasons.

MTN has a presence in 21 countries in Africa and the Middle East.

Reporting by Tanisha Heiberg; editing by Jason Neely