It comes just a day after another migrant boat sank in the region, which the UN's refugee agency described as "the worst in the Aegean this year".
ADVERTISEMENTGreek officials said on Friday that eleven people had died in the sinking of a migrant boat that had run aground on a small island the previous day.
Some 90 survivors, including 52 men, 11 women and 27 children, were evacuated Friday morning from the islet north of the Greek island of Antikythera, a Greek coastguard official told AFP.
Search and rescue operations were continuing as the exact number of people on board the boat remained unclear.
The Greek office of the UN refugee agency UNHCR said the "boat tragedy" shows that "people need safe alternatives to these perilous crossings".
Thursday's sinking came a day after a dinghy carrying migrants capsized off the island of Folegandros, also in southern Greece, killing at least three people.
Thirteen people — mainly Iraqis but also Syrians and Egyptians — were rescued, but dozens more are still missing, according to Greek authorities.
Survivors gave conflicting accounts, with some saying there were initially 32 people on board, while others put the figure at around 50, a coastguard official told AFP.
UNHCR said the sinking off Folegandros was "the worst in the Aegean this year", adding that the shipwreck was "a painful reminder that people continue to embark on perilous journeys in search of safety."
The UN agency estimates that more than 2,500 people died or disappeared at sea trying to reach Europe between January and November.
Nearly one million people, mainly Syrian refugees, arrived in the EU in 2015 after a journey from Turkey to nearby Greek islands.