Thirty-four refugees have drowned off the Greek island of Farmakonisi, believed to be the largest recorded death toll from any single accident in Greek waters since the migrant crisis began.
The latest deaths in the Aegean Sea came as Athens angrily defended its handling of the mounting migrant crisis in Europe.
Four babies, six boys and five girls died when the boat sank off Farmakonisi.
Another 68 people were plucked alive from the sea while a further 29 managed to swim to safety on a beach on the island, the coastguard said.
The coastguard was also still searching for four children missing when another boat capsized yesterday off Samos, a Greek island close to the Turkish coast.
Tens of thousands of migrants from Syria and Afghanistan have braved the treacherously rough seas this year from the Turkish coast to Greece's eastern islands.
More than 380,000 people have arrived in Europe by sea this year, figures from the UN's refugee agency UNHCR showed, including close to 260,000 in Greece and 121,000 in Italy.
They are frequently squeezed together in flimsy and overcrowded inflatable dinghies.
The latest tragedy follows the death of three-year-old Syrian boy Aylan Kurdi whose lifeless body was pictured face down on a Turkish beach, which sparked an international outcry over the human cost of the crisis.
He drowned along with his mother Rihan and five-year-old brother Galip when their boat capsized on a short journey from Turkey to the Greek island of Kos.
Greek interim Prime Minister Vasiliki Thanou has called on the European Union to agree a more comprehensive policy for dealing with the rising numbers fleeing to the region to escape war and poverty.
She said: "Greece is strictly applying European and international treaties without ignoring the humanity of the situation."
The vast majority of refugees reaching Greece quickly head north to other countries, with Germany the most favoured destination.
Europe as a whole is struggling to deal with an enormous influx of people, mostly from Syria but also Afghanistan, Eritrea and other countries, fleeing violence and poverty.
The European Commission announced plans last week for mandatory quotas to share out 120,000 additional asylum seekers among 25 member countries.
But many countries such as Hungary, Czech Republic Slovakia and Romania are opposed to this.
- Daily Mail