A fishing boat packed with migrants is feared to have had up to 100 children trapped in the hold when it sank off the coast of Greece.
At least 78 people have already been confirmed dead in one of the worst migrant disasters in Europe’s history.
So far 104 survivors travelling from Libya to Italy have been rescued, but hundreds more are missing.
The boat was estimated to be carrying up to 750 people when it capsized and sank at around 2am on Wednesday morning, according to the UN migration agency, known as IOM.
A senior doctor at Kalamata General Hospital, in southern Greece, who treated survivors said they believe as many as 100 children were onboard.
Dr Manolis Makaris, head of cardiology, told the BBC : “They (the survivors) told us that there were children in the bottom of the ship. Children and women.”
He said two patients had given him estimated figures.
“One told me about 100 children, the other about 50, so I don’t know the truth - but it is many,” he added.
Rescue ships desperately searched the Mediterranean on Thursday for survivors, but experts warned the chances of finding passengers alive were dwindling.
Retired Greek coast guard admiral Nikos Spanos said: “The chances of finding (more survivors) are minimal.”
An aerial photograph of the vessel before it sank released by Greek authorities showed people crammed on the deck. Most were not wearing life jackets.
Experts believe the boat may have sunk after running out of fuel or suffering engine trouble, with movement of passengers causing it to list and ultimately capsize.
Greece’s coastguard has been criticised for not intervening earlier, amid reports of distress phone calls being made by migrants onboard as early as 3pm the previous day, but authorities claim their offers of aid were refused.
Greece’s public broadcaster ERT is reporting that 11 to 12 arrests have been made at the Kalamata Port Authority.
The country declared three days of mourning and politicians suspended campaigning for a general election on June 25.
A Supreme Court prosecutor ordered an investigation into the circumstances of the deaths.
Meanwhile survivors, including Egyptians, Syrians, Pakistanis, Afghans and Palestinians, were desperate to contact their families and trace the missing.
“The survivors are in a very difficult situation. Right now they are in shock,” said Erasmia Roumana, head of a United Nations Refugee Agency delegation.
“They want to get in touch with their families to tell them they are OK, and they keep asking about the missing. Many have friends and relatives unaccounted for.”
Brit Aftab Khan, from Wolverhampton, travelled to Greece following the tragedy.
He told Sky News 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.”
Meanwhile Mohamed Abdi Marwan, from Kobani, a Kurdish majority town in northeastern Syria, said that five of his relatives were on the boat, including a 14-year-old.
He said that each of his relatives paid $6,000 for the trip.
“Those smugglers were supposed to only have 500 on the boat and now we hear there were 750. What is this? Are they cattle or humans? How can they do this?” Marwan added.
The boat capsized close to the deepest part of the Mediterranean Sea, where depths of up to 17,000 feet (5,200 meters) could hamper any effort to locate a sunken vessel.
Ursula von der Leyen, the European Commission president, said she was “deeply saddened” by the tragedy and promised to strengthen cooperation between the European Union and nearby countries to try to further crack down on migrant smugglers.
But human rights groups argue that the crackdown has forced migrants and refugees to take longer and more dangerous routes to reach safe countries.
The IOM has recorded more than 21,000 deaths and disappearances in the central Mediterranean since 2014.
