At least 30 people were killed and 36 injured in a collision between two buses on Harare-Bulawayo Highway in Zimbabwe, the media reported on Friday.One bus suffered a tyre-burst and side-swiped a Mercedes Benz Sprinter commuter omnibus along the highway on Thursday, Xinhua quoted police as saying.Abigail Moyo, senior assistant commissioner of police in Midlands province, said 28 people were killed on the spot and two died in hospital.A total of 32 people were in critical condition, she said.The accident is one of the major road accidents in recent months in Zimbabwe, which frequently suffers road fatalities due to over-speeding and the country's poor road conditions, among other factors.