At least 18 people have been killed on Saturday when a passenger train smashed into the back of another train on Indonesia’s Java Island, police said.

Police said a traffic management error was to blame for the accident, which occurred in the early morning at the station in Petarukan Pemalang, Central Java province.

Police at the scene said 18 people were killed and many more were injured when a train headed to Surabaya slammed into the back of a Semarang-bound train that was sitting idle at the platform.

National police spokesman Iskandar Hasan however put the toll at 10 killed, while state-run news agency said nine.

“The suspected cause of the accident was a mistake in the traffic management system,” Hasan said.