According to the coastguard, at least 15 people including six children have died after their boats sank off the Greek islands of Farmakonisi and Kalolimnos early Friday morning, while many other refugees are reported missing.
The first boat hit rocks at approximately 0030 GMT as it was making the perilous crossing from Turkey. Port police reports said 48 survivors reached the shore of Farmakonisi.
The coastguard found bodies of six children and a woman.
The second boat capsized off the Aegean island of Kalolimnos hours later. Port police recovered eight bodies, with the 26 survivors reporting that dozens of people had been on the boat.
The port police said they were searching for the missing people.
Thousands of people are still making the perilous journey from Turkey in flimsy boats every day, as they flee war and persecution in the Middle East and elsewhere. Many of them are coming from Syria and braving the journey in spite of the harsh winter weather and the risks.
According to International Organization for Migration estimates, approximately 31,000 of refugees made it to Greece by sea this year, in the hopes of rebuilding their lives in Germany, Sweden and other countries in the European Union.
The IOM reported 77 people died between January 1 and January 17, as they attempted to cross the Mediterranean Sea.
On Thursday at least 12 people, including children, drowned off the Turkish coast on a boat headed for Greece. The Turkish coastguard rescued 28 people.