The incident occurred off Ayvacik district as an inflatable boat, packed with more than 20 people, sailed to the nearby Greek island of Lesbos, Canakkale Provincial Governor Hamza Erkal told Anadolu Agency.

The Turkish Coast Guard found the bodies of the 13 dead people. Eight people were rescued, who were taken to hospital, Erkal said.

A search-and-rescue operation is underway to find any more survivors or victims, he added.

The Greek Coast Guard said it rescued two more women refugees later on Sunday; the Syrian women were taken to hospital.

According to the International Organization for Migration, there have been more than 2,700 migrant fatalities in the Mediterranean Sea this year, 103 of them in the waters between Greece and Turkey.

Greece has received more than 309,000 refugees this year, mostly Syrians fleeing the civil war.

In the first five months of 2015, over 42,000 people arrived by sea to Greece, most of them refugees, according to the United Nations Refugee Agency (UNHCR).

However, the UNHCR also says more than 300,000 people have risked their lives to cross the Mediterranean Sea so far this year, with around 2,500 refugees and asylum seekers have died or gone missing trying to reach Europe.