The boat capsized off the coast of the Sultaniçe district in the town of Enez, said the sources, who spoke on condition of anonymity due to restrictions on talking to the media.
The Coast Guard reached five bodies in the sea. No further details on the incident were provided.
On a related note, at least 402 irregular migrants were detained across Turkey, security sources said on Sept. 28.
In the eastern Van province, 91 irregular migrants—including Afghan and Pakistani nationals—were rounded up by security units, said a security source.
Separately in the northwestern province of Çanakkale’s Ayvacık district, 33 Afghan nationals, including women and children, were rounded up.
At least 28 irregular migrants were detained off the coast of the southwestern Muğla province, while 150 migrants who were preparing to go abroad were rounded up in the northwestern province of Edirne.
In northeastern Artvin, 28 migrants were detained in a bus.
In addition, 58 Afghan and Pakistani nationals were rounded up in the eastern province of Malatya.
Also, 14 irregular migrants were detained in the Bodrum district of Muğla.
All of the migrants were referred to provincial migration offices.
Turkey has been a major route for refugees trying to cross into Europe, especially since the beginning of the Syrian civil war in 2011.