MTN Group’s first-half earnings rose as Africa’s largest wireless carrier pushed ahead with an asset disposal plan and saw strong profit growth in its biggest market of Nigeria.

The Johannesburg-based mobile phone company said earnings before interest, taxes, depreciation and amortisation rose 10%, while sales also gained 10%.

MTN is now about six months into a plan to raise about R15-billion from disposals to help pay down debt, which increased to R70.1-billion rand in the first half. Even so, the carrier is seeking to add Ethiopia to its 21 markets, with a potential auction of new licences to take place by 2020.

A headache for for MTN is — as ever — its biggest market of Nigeria, where the company is still struggling to resolve a US$2.2-billion tax claim that’s delayed a plan to sell down a stake in its local unit. Africa’s most populous nation continues to pay its way, however, with earnings gaining 16% over the half year.

MTN is among carriers suffering an interminable wait for the auction of new spectrum in South Africa. In the meantime, the carrier extended a roaming agreement with struggling rival Cell C on Wednesday to cut costs for both groups.