As many as 50 vessels have been trapped in ice in the Baltic Sea, with a number of passenger ferries among those stranded.
Many of the vessels were attempting to navigate passage from Finland to Sweden, subsequently becoming stuck in the Gulf of Bothnia or Baltic Sea.
Ice breaking vessels from both nations have arrived on the scene and are attempting to free the ships.
Some vessels have been trapped for several days. Hundreds of passengers in ferries operated by Viking Line, Anedin Lines and Tallink have been offered free food and alcohol while awaiting rescue.
Viking Line has cancelled a number of departures, with other carriers expected to follow.
“This is the worst ice cover we have seen since 1996,” explained said Johnny Lindvall, head of the ice-breaking unit at the Swedish Maritime Administration.
Mr Lindvall added that ice would not usually be a problem for merchant ships.
However, winds of approximately 20 metres per second were moving ice quickly across the water, creating ridges and making passage difficult.
Finnfellow, operated by Finn Lines, and Viking Line’s Amorella were among the vessels in difficulty.