Immigrants arrive at the port of Chania on the island of Crete on April 1, 2014.
At least 18 migrants drowned and many more remained missing in the Aegean Sea on Monday after a yacht and a dinghy carrying them towards Greek shores capsized, coastguard officials said.
Fourteen of the dead were found on board the 10-meter (33-foot) yacht after it was towed to shore, the coastguard said, adding that the bodies of another four people had been recovered at sea.
Thousands of migrants from Africa and the Middle East pack into often unsafe boats to get into the European Union via Greece, Italy, Malta and other coastal states.
More from GlobalPost: Italy rescues 1,800 more migrants from boats in rough seas
The numbers have increased since "Arab Spring" uprisings triggered unrest across North Africa and civil war in Syria.
Authorities said they did not yet know the nationality of the migrants. Two air force helicopters, assisted by two coast guard vessels, one navy warship and a cruise liner were searching for the missing, the coast guard official said.
More from GlobalPost: A European tragedy
Greece, Italy and Malta have repeatedly pressed European Union partners to do more to help them handle the large numbers of migrants.
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