MADRID: Seventeen people were found dead on a migrant boat off El Hierro in Spain’s Canary Islands on Monday and three other people were rescued, the country’s maritime rescue service said.

The vessel was spotted some 265 nautical miles southeast of El Hierro and an air force helicopter was deployed to airlift the three survivors, a spokeswoman for the service said.

“The three had hypothermia but were otherwise in good shape,” she told AFP, adding they were being taken by helicopter to a hospital on El Hierro.

The migrants on the boat were all sub-Saharan Africans, the spokeswoman said. It was not immediately clear where the boat had embarked from. Earlier this month four people were found dead in a makeshift boat that was found south of El Hierro, with 23 migrants on board.

At its shortest, the sea crossing to the Atlantic islands from the Moroccan coast is around 100 kilometres (60 miles), but it is a notoriously dangerous route because of strong currents. Vessels are also typically overcrowded and in poor condition. Migrant arrivals on the archipelago surged after increased patrols along Europe’s southern coast dramatically reduced crossings to the continent via the Mediterranean.