South Africa's MTN Group now owns 97.34 percent of MTN Uganda following the announcement of $55 million cash purchase on Monday.

The South African cellular network provider acquired 12.89 percent of the Ugandan company from Rwanda-based Tri-Star Investments S.A.R.L., an investment holding company.

"MTN Uganda has performed well over the years amid intense competition, giving us confidence in the business, said MTN vice-president Irene Charnley in a statement.

The purchase means MTN Group will acquire all of MTN Uganda's 1,128,000 subscribers.

MTN is already Africa's biggest operator by far, serving 24-million customers. This is set to grow substantially following its recent $5.5 billion acquisition of Lebanon-based Investcom which has 2.66 million users in Africa and 4.9 million in the Middle East.

The MTN group had upped its stake in MTN Uganda earlier this month. It bumped its ownership of the company 32.44 percent after buying shares from Sweden's Overseas Telecom AB for $164 million.

In 1998, the MTN Group was awarded Uganda's second national operator license, which included a GSM license, making it the only operation in the Group that operates both mobile and fixed lines.

Since December 2005 till September this year, MTN has committed to invest $36 million in network infrastructure which will demonstrate the Group's ongoing commitment to Uganda.

Rwanda Mtn