A bus carrying 34 passengers sped out of control on a downhill road and overturned in Indonesia’s West Sumatra province on Tuesday, killing at least 12 people and leaving others injured, police said.

The inter-province bus was on its way to Indonesia’s capital, Jakarta, from Medan in North Sumatra province when its brakes apparently malfunctioned near a bus terminal in West Sumatra’s Padang city, said Reza Chairul Akbar Sidiq, the director of West Sumatra traffic police.