At least 14 migrants, including four children, died when a boat carrying about 20 people capsized overnight in the Aegean Sea, Greek police said Saturday.
The boat was ferrying migrants from Turkey to Greece. Police recovered eight more bodies after the corpses of a man, a woman and four children surfaced off the island of Agathonissi.
Two women and a man who managed to swim to safety sounded the alarm. Survivors said the boat was carrying 21 people, according to port officials.
A patrol boat, a military helicopter and three fishing vessels are taking part in the rescue operation and officials are waiting for reinforcements from Frontex, the European border agency.
Frontex said last month that in 2017, the European Union saw the lowest number of detected illegal border-crossings since the migrant crisis began four years ago.
The number dwindled to 204,700 from 1.8 million in 2015, it said. The drop was especially observed on the eastern Mediterranean migratory route which connects Turkey to Greece, and the central Mediterranean route connecting Libya to Italy.
The EU last year reached deal with Turkey in 2016, which sharply reduced the number of people crossing to Greece.
It has been criticised by humanitarian workers as it stipulates that all arrivals will be sent back to Turkey, including Syrian refugees. Greece is also detaining thousands of migrants in overcrowded squalid camps.