A passenger ferry ran aground Saturday next to islands between Sweden and Finland, leaving nearly 430 passengers and crew stranded for the night, the Finnish owner and coast guard said.

The Viking Line's "Grace," sailing between the Finnish port of Turku and the Swedish capital Stockholm, hit rocks around 1415 pm (1215 GMT) shortly before a stopover in Mariehamn, in the Aland archipelago, Finland's coast guard said.

It said the cause of the accident was not immediately known but there were powerful winds in the region.

"There is no water leak and no immediate threat" to passengers, the coast guard said on Twitter.

Aboard the vessel were 331 passengers and 98 crew, a Viking Line spokeswoman told AFP.

The Viking Line cruise ship Viking Grace ran aground with some 300 passengers on its way from Finland to Sweden
The Viking Line cruise ship Viking Grace ran aground with some 300 passengers on its way from Finland to Sweden Lehtikuva / Niclas Nordlund

"The passengers will have to spend the night on board and disembark (Sunday)," the spokeswoman said.

"The ship's situation is stable. On Sunday we will tell the passengers which ship they can take to return to Sweden and Finland."

Divers were inspecting the hull to determine how to put the ship back in operation.

"The situation on board is calm and a dinner is being served," the company told AFP around 1700 GMT.

Because of a storm warning, the company said it had decided to use the "Grace" instead of a smaller, less sturdy vessel.

In September, another Viking Line ferry, the Amorella, ran aground by the same Aland archipelago and passengers had to be evacuated.