KALAMATA, Greece — 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 that the migrants repeatedly refused assistance and insisted on continuing to Italy.

Legal experts said that was 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 that 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, 34, said he got the first flight from Germany to Greece after realizing his wife and brother-in-law were on 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 Syrian refugee living in Hamburg, said Esra Aoun, 21, and her 19-year-old brother, Abdullah, risked the 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 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 U.N. migration agency, known as IOM, estimated the number of passengers based on interviews with survivors and said the passengers included at least 40 kids.

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 has heard nothing about them since the vessel sank.

He believes his nephew Ali Sheikhi, 29, is alive, after relatives spotted him in photos of survivors, but that has not been confirmed.

“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 activists said they received repeated distress calls.