A number of Palestinian families have expressed deep concern over the fate of their missing relatives after a migrant boat sank off the Turkish seashore, resulting in deaths.

Turkey's Ministry of Interior said eight people, including three women, have drowned after a boat carrying migrants sank late on Thursday off the coast of Fethiye, in Turkey's southwest.

The coastguard dispatched three boats, a team of divers, a plane and a helicopter to the area as soon as it received word of the incident.

A search-and-rescue mission continued for seven migrants thought to be missing.

There has been no information yet on the nationalities of the migrants who were on the boat.

Turkey is a main crossing point for migrants, including Palestinian refugees, trying to make their way to Europe to escape violent conflicts or economic hardship.

Rights groups have kept record of the death of dozens of Palestinian refugees onboard Europe-bound boats, as they fled war-torn Syria to Turkey, before heading for neighboring Greece and other coastal destinations.

A deal between Turkey and the European Union in 2016 helped stem migration flows, but many asylum-seekers still attempt the dangerous trip across the Aegean Sea to Greek islands.