An oil tanker truck rolled down a hill and smashed into four minibuses in rural Kenya, killing 29 people and injuring more than 30, police said Friday.

The tanker's driver had stopped to refuel Thursday when the vehicle started rolling, Police Chief Grace Kaindi in Kisii, about 165 miles west of the capital, Nairobi.

Hospitals treated dozens of people and the death toll was expected to rise.

Kaindi said the accident was still under investigation.

On Tuesday, another crash in the area killed 22 people when they bus they were traveling in rammed a truck head-on. Kisii and the surrounding towns are rural and depend largely on tea farming.

Road accidents are common in much of Africa, where poor road conditions coupled with badly maintained vehicles make for precarious driving conditions.