Updated

Greek authorities say more than 20 migrants have been rescued after their boat either sank or capsized overnight near the small southeastern island of Kastellorizo, while a child among them died later in a hospital.

Greece's coast guard said Thursday a vessel from the European border agency Frontex initially picked up six people found in the sea northwest of Kastellorizo, and a search was begun to find other potential survivors.

One of the six, a 9-year-old girl, was transported to a hospital but later died, the coast guard said. Search crews later found and rescued another 20 people from the island's rocky coast.

It was unclear what type of vessel the migrants had used. The coast guard said the search and rescue operation was continuing.