The accident occurred late on Sunday near the Tanzanian town of Mbeya, some 800 kilometres (500 miles) south of the country's commercial capital of Dar es Salaam, they said>
Mbeya regional police commander Suleiman Kova told AFP that the bus, which was en route from Lusaka to Nairobi through Tanzania, overturned at the Chimala village.
"We are still investigating on the cause of the accident," he said, saying it was too early to identify the dead by name or nationality.
Road accidents are common in the east African nation and police usually blame them on violations of the traffic regulations, poor road or vehicle conditions and exhaustion among long-distance drivers.
In June, two horrific accidents, one involving an overloaded bus and one involving a cargo truck, killed at least 84 people in northern Tanzania.

Copyright AFP (Agence France-Presse), 2006