The search for missing twins from Switzerland has spread to Corsica after French authorities confirmed they were spotted on board a ferry to the Mediterranean island.

The six-year-old twins and their father were seen by several people on board the Marseille-Propriano ferry on the night of January 31.

The father was also spotted leaving ferry the following morning, accompanied by two girls who could not be positively identified, Swiss police said.

It is the first confirmed sighting of the twins since January 30 when their father abducted them from Saint Sulpice near Lausanne, where they live with their Italian mother.

On Thursday Vaud police announced they had stopped searching around Saint Sulpice and were concentrating on the father's private and work life.

The mother made an appeal on Italian television on Wednesday for witnesses to come forward. "Help us to find them. It is my hope that they are still alive," she told a crime watch programme.

Police from Switzerland, France and Italy are trying to trace the movements of the 43-year-old Canadian-born father up until Thursday night, when he committed suicide in the southern Italian town of Cerignola. 

Swiss police said the father sent €4,400 (SFr5,788) in an envelope to his wife from the Italian town of Bari and more money had been posted near the spot where he threw himself under a train.

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