An American woman has disappeared after failing to return to her cruise ship while visiting the Caribbean, sparking a search effort across the island of St. Martin.

According to the St. Martin Police Force (KPSM), Ann Evans, 55, was a passenger on the cruise ship Rotterdam, which made a stop in Port St. Martin on November 20. Evans joined an organized island tour but, after leaving the bus in Marigot on the French side of the island, she did not return to either the tour bus or the ship.

The Government of Sint Maarten has issued a missing persons alert, stating that authorities from both the Dutch and French regions of the island have been notified and are actively involved in the search for Evans. Their efforts to locate her are ongoing.

Details about whether Evans was accompanied by anyone during her travels or if she was on the cruise alone have not been disclosed.

Per its website, Rotterdam is the newest ship in Holland America Line. The ship can house upwards of 2,600 passengers at double occupancy or up to 4,173 guests when its staterooms are fully booked.

KPSM and the French Gendarmerie are urging anyone with information about Evans’ whereabouts to come forward.