At least 60 illegal immigrants, most of them Palestinian and more than half of them children, died after their overcrowded fishing boat sank off Turkey's western Aegean coast, according to Reuters .

About 100 people were originally on board, a district official said on Thursday.

The remaining 46 survivors, including the ship's Turkish captain and his assistant, swam through the Aegean waters to shore, only 50 metres away.

Tahsin Kurtbeyoglu, the governor of the coastal district of Menderes in Turkey's western Izmir province, said an initial investigation showed the small vessel sank due to overcrowding around dawn.

"The latest death toll we have is 60 people, including 11 men, 18 women and 31 children, including three babies," Kurtbeyoglu told Reuters.

Trapped below deck

The survivors said several people had been trapped below the deck of the submerged vessel, and divers launched an operation to try to find them.

The group had previously made their way to hotels in the city of Izmir, where smugglers agreed to take them to Britain. Authorities arrested two Turkish suspects in the smuggling operation, Turkey's TRT television reported.

Those who survived were on the deck, rather than below with other members of their group. It was not immediately clear when the boat sank, but many such vessels carrying illegal immigrants make the journey at night.

Illegal immigrants from Asia and Africa have long sought to reach Europe by passing through Turkey, and their desperate efforts have occasionally ended in disaster. Each year, thousands try to sail to Greek islands from Turkish soil in rickety boats.

Turkey is now hosting 80,000 Syrians who have fled the civil war in their country, with most staying in camps near the border. Some countries are concerned that larger numbers of Syrians could try to reach Europe illegally; Greece said in July that it was quadrupling the number of guards at its border with Turkey and boosting other defence in part because of worries about a potential influx.