At least six people on board a passenger train were killed after the locomotive collided with falling debris from an oncoming freight train on the Great Belt bridge, reports said. Sixteen people sustained injuries in the accident but are not critically hurt, Danish media reported.

A storm has hindered efforts to rescue around 100 passengers from the Great Belt bridge which links Zealand and Funen.

Banedanmark, which maintains and controls rail network traffic, said the train was heading towards Copenhagen. The accident is believed to be the worst in the country in over 30 years, AP reported.

An initial inquiry by the Danish Accident Investigation Board indicates that the incident occurred after a trailer was blown off a freight train carrying packaging for Danish beer maker Carlsberg. “This morning’s tragic accident on the Great Belt Bridge with many killed and wounded has shaken us all,” Danish Prime Minister Lars Lokke Rasmussen tweeted. “Ordinary Danes on their way to work or on the way home from Christmas holidays have had their lives shattered.”

Around 21,000 train passengers commute on the bridge, that links Denmark and Sweden to Germany, daily.