Danish police has confirmed that six people were killed and 16 others injured in the train accident on a bridge linking central Denmark’s islands.

Police said the passenger train had hit an “unknown object” but did not further comment. Danish Railways earlier told Denmark’s TV2 that the victims were passengers on a train going from the city of Odense to Copenhagen when the accident took place Wednesday morning.

Danish media reported that a tarpaulin on a freight train hit the passenger train, which was going in the opposite direction, prompting it to brake suddenly.