Aftab Khan, from Wolverhampton, travelled to Greece following the tragedy in the early hours of Wednesday morning.

At least 78 people drowned and 104 were rescued after the fishing vessel capsized about 50 miles from the southern coastal town of Pylos.

Charity Alarm Phone, which received frantic calls from some of those on board, said up to 750 people may have been on the vessel at the time and a massive search operation for survivors is continuing.

Nine of the survivors have been arrested on suspicion of being part of the smuggling ring that arranged the journey, said the coastguard.

Mr Khan told Sky News' Middle East correspondent Alistair Bunkall that one of his male cousins had been found alive but he had been unable to find two others.

Speaking in the port city of Kalamata, where survivors have been brought by rescuers, he added: "We don't know where the rest of them are at the moment.

"We're just trying to find out."

Greek officials said the boat got into difficulties when its engine stopped and it began veering from side to side. It then capsized and sank at around 2am on Wednesday.

Aerial pictures released by the Greek coastguard showed the 20m to 30m-long boat hours before it sank.

Dozens of people on the upper and lower decks were seen looking up, some with arms outstretched.

Witnesses said many more women and children were below in the hold.

Three days of national mourning have been declared by the Greek government.

Shortly before the boat sunk, Alarm Phone said it spoke to someone on board who said: "The captain left on a small boat. Please, any solution."

They also pleaded for food and water, and said the vessel had stopped moving.

The charity also accused the Greek and other European authorities of failing to launch a rescue operation before the boat went down, despite being "well aware of this overcrowded and unseaworthy vessel".

The Greek coastguard denied the claim and said those on board "refused our assistance because they wanted to go to Italy".

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Survivors were brought to the port city of Kalamata by the coastguard early on Thursday. Many are being treated for conditions including hypothermia and dehydration.

Greek authorities, who initially said 79 people had died before later revising the figure down to 78, said they could not confirm how many people were on board.

The UN's International Organization for Migration said initial reports suggested there were up to 400 people on the vessel, while the deputy mayor of Kalamata told Sky News it was probably around 550.

The boat is thought to have set off from the Libyan port of Tobruk and was heading to Italy.

Greek authorities said most of the migrants were from Egypt, Syria and Pakistan.

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