A police officer looks on near a damaged cargo train compartment near the Storebaelt bridge, near Nyborg in Denmark, Wednesday, 2 January 2019. (Michael Bager/Ritzau Scanpix via AP)

COPENHAGEN, Denmark — A passenger train on a bridge linking central Denmark’s islands hit an “unknown object” early Wednesday, killing six people and injuring 16 others, Danish police said.

The rail operator, Danish Railways, earlier told Denmark’s TV2 that the victims were passengers on a train going from the city of Odense, on the central Danish island of Fyn, to Copenhagen when the accident took place about 8 a.m. local time.

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 violently. Police spokesman Arne Gram said the passenger train “hit an unknown object,” but did not further comment.

Photos from the scene show the freight train was carrying crates of beer, and the tarpaulin that covered the train was torn in pieces.

Kasper Elbjoern, spokesman for Danish brewery group Carlsberg, confirmed that a freight train transporting its cargo was involved in the accident.

Jesper Nielsen, who was on the passenger train, told Denmark’s TV2 the train “was out on the bridge when there was a huge ‘bang’ …. very quickly thereafter, the train braked.”

The Storebaelt bridge is part of a system of bridges and a tunnel linking the Danish islands of Zealand and Funen.

Flemming Jensen, the CEO of state-owned Danish Railways, said police and the Danish Accident Investigation Board are investigating the damages. He said the operator “will contribute everything that we can to the investigations.”

In a statement, police urged passengers to contact next of kin to inform them of their safety and urged people not to share photos and videos of the accident.

The accident took place on a road-and-rail bridge, part of a transport system consisting of a road suspension bridge and a railway tunnel.

The transport system was closed to cars overnight because of strong winds but trains could pass. Road traffic resumed Wednesday with a 50 kph (31 mph) speed limit.