Jakarta. The Jakarta-Bandung high-speed train project co-funded by Chinese investors was suspended after a rail track maintenance train derailed in West Java and killed two Chinese workers on Sunday.

A maintenance train belonging to Kereta Cepat Indonesia China (KCIC) -- the consortium which runs the project -- was speeding on the half-finished track before it overturned in the West Java town of Padalarang on Sunday evening.

"We are investigating why the train overshot the unfinished rail track," Transportation Ministry's railway safety director Edi Nursalam told BTV news broadcaster at the scene.

At least five people were injured in the accident.

The Transportation Ministry suspended the project to allow a full investigation into the case, the ministry's spokeswoman Adita Irawati said in a statement.

"After the investigation is concluded, the findings will be submitted upon which recommendations will be made to boost the safety aspects in railway construction," Adita said.

The National Police said at least 18 witnesses have been questioned in relation to the accident, which occurred only a month after President Joko Widodo and his Chinese counterpart Xi Jinping checked the progress of Indonesia's first high-speed train project via video conference during their meeting in Bali.

"The focus of the investigation is to determine the cause of the accident and it will involve experts from the KNKT (National Transportation Safety Committee) and the railway company, and if necessary we will [interrogate] representatives of the train supplier," police spokesman Insp. Gen. Dedi Prasetyo told reporters in Jakarta.