At least 15 people were killed after a passenger bus overturned on a toll road on Indonesia’s main island of Java early Monday, according to emergency officials.

The inter-province bus was carrying 34 passengers when it lost control shortly after midnight while travelling from the capital, Jakarta, to the historic city of Yogyakarta. The vehicle struck a concrete barrier and rolled onto its side, said Budiono, a regional search and rescue agency chief who uses a single name.

Rescue teams were dispatched to the scene and worked through the night to evacuate victims and provide medical assistance to survivors. Several passengers were taken to nearby hospitals with injuries, though officials had not released an updated count of the wounded by Monday morning.

Deadly road accidents remain a persistent concern in Indonesia, where long-distance bus travel is common and road safety enforcement can vary across regions. Authorities said the cause of the crash was still under investigation, including whether speed, road conditions, or driver fatigue played a role.

Officials have urged transport operators to comply with safety regulations, particularly during overnight travel on major highways, as the country continues to record high traffic fatality rates.