ATHENS — Nine survivors of a migrant boat sinking were arrested Thursday on suspicion of smuggling as hope faded for hundreds of other passengers who were missing and attention turned to Greece's failure to act before the overcrowded ship capsized.

The trawler may have carried as many as 750 passengers, including women and children who were likely trapped in the hold as the vessel overturned and went down early Wednesday. That could make the sinking one of the deadliest ever in the central Mediterranean Sea.

A huge search-and-rescue operation initially recovered 78 bodies and picked up 104 survivors — all men and boys. But no more have been found.

Meanwhile, Greek authorities were criticized for not acting to rescue the migrants, even though a coast guard vessel escorted the trawler for hours and watched helplessly as it sank in minutes. Greek officials argued the migrants repeatedly refused assistance and insisted on continuing to Italy, but legal experts said that is no excuse.

The coast guard said late Thursday that it had arrested nine survivors on suspicion of belonging to the smuggling ring that arranged the voyage. State-run ERT TV said the suspects were all Egyptians, adding the ship originally left an Egyptian port for the area of Tobruk in eastern Libya, where it picked up the migrants.

Relatives of the migrants — who each paid thousands of dollars for passage on the battered vessel — gathered in the southern port city of Kalamata to look for their loved ones.

Kassem Abu Zeed said he caught the first flight from Germany to Greece after realizing that his wife and brother-in-law were aboard the trawler.

“The last time we spoke was eight days ago, and (my wife) told me that she was getting ready to get on the boat,” Abu Zeed told The Associated Press.

“She had paid $5,000” to smugglers. “And then we all know what happened.”

Abu Zeed, a 34-year-old Syrian refugee living in Hamburg, said Esra Aoun, 21, and her 19-year-old brother, Abdullah, risked the dangerous crossing from Libya to Italy after they failed to find a legal way to join him in Germany.

The chances are low that Abu Zeed's wife survived the sinking about 75 kilometres (45 miles) offshore. None of those rescued were women.

Now he hopes Abdullah may be among the men from Syria, Egypt, Pakistan and the Palestinian territories who are being temporarily housed in a Kalamata warehouse or recuperating in hospitals from hypothermia and exposure.

The chances of finding more survivors "are minimal,” retired Greek coast guard Adm. Nikos Spanos told ERT.

The UN migration agency, known as IOM, estimated the number of passengers based on interviews with survivors and said the complement included at least 40 children.

Erasmia Roumana, head of a United Nations refugee agency delegation, said many of the survivors have friends and relatives unaccounted for.

“They want to get in touch with their families to tell them they are OK, and they keep asking about the missing,” Roumana said.

Mohamed Abdi Marwan, who spoke by phone from Kobani, a Kurdish-majority town in Syria, said five of his relatives were on the boat, including a 14-year-old. Marwan said he’s heard nothing about them since the vessel sank.

“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 said. He said each of his relatives paid $6,000 for the trip.

Greek authorities said the vessel appeared to be sailing normally until shortly before it sank and refused repeated rescue offers. But a network of activists said they received repeated distress calls from the vessel during the same time.

The Greek coast guard said it was notified of the boat's presence late Tuesday morning and observed by helicopter that it was “sailing on a steady course" at 6 p.m.

A little later, Greek search-and-rescue officials reached someone on the boat by satellite phone, who repeatedly said that passengers needed food and water but wanted to continue to Italy.

Merchant ships delivered supplies and observed the vessel until early Wednesday morning when the satellite phone user reported a problem with the engine. About 40 minutes later, according to the coast guard statement, the migrant vessel began to rock violently and sank.

Coast guard experts believe the boat may have run out of fuel or experienced engine trouble, with the movement of passengers causing it to list and capsize.

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.

The trawler sank near the deepest part of the Mediterranean, where depths of up to 5,200 meters could hamper any effort to locate a sunken vessel.

Human rights groups say a European Union crackdown on smuggling has forced people to take longer, more dangerous routes to reach safe countries.

Eftychia Georgiadi, an official in Greece with the International Rescue Committee charity, said the EU’s failure to offer safer pathways to migration “effectively slams the door on people seeking protection.”

“Nobody embarks on these treacherous journeys unless they feel they have no other option,” she said. — Euronews