POZZALLO, Italy -- It was the cries of children -- and the moment they decided they must save themselves -- that haunt the survivors of a shipwreck that claimed hundreds of lives.

Two Eritreans who arrived safely in Sicily told The Associated Press on Sunday how the sea kept seeping into their rickety fishing boat despite all efforts to bail the water out. Eventually, the sea prevailed.

Between 400 and 550 on their smugglers' boat didn't make it, part of the estimated 700 migrants who perished in Mediterranean Sea shipwrecks over three days last week in the deadliest known tally in over a year, as calm weather and sunny skies increased smuggling crossings from Libya.

"When the morning came, I saw how the children were crying and the women," Habtom Tekle, a 27-year-old Eritrean, told the AP through an interpreter. "At this point I only tried to pray. Everybody was trying to take the water out of boat."

The rickety wooden boat without an engine was being towed by another smugglers' boat laden with hundreds of other migrants, signalling the increasing desperation of the smugglers. Once the second boat started sinking Thursday, the commander on the first boat ordered the tow line cut, apparently to keep his boat from sinking as well, according to Italian police interviews of survivors.

The line, at full tension, whipped back, fatally slashing the neck of a female migrant, police said.

By then, Filmon Selomon, a 21-year-old Eritrean, had plunged into the sea. He told the Associated Press that knew he could only save himself.

"I started to cry when I saw the situation and when I found the ship without an engine. There were many women and children," he said. "Water was coming in from everywhere, top, bottom."

Tekle described people holding onto each other, some dragging others underwater, as the boat was sinking.

"For me, it was very shocking," he said through an interpreter.

Police put the number below deck at 300 and said they all perished as the boat sank. Some 200 more plunged into the sea, but only 90 of those were saved, along with 500 from the first boat.

A 17-year-old Eritrean, Mohammed Ali Imam, who arrived on Sicily five days ago in another rescue, told the AP that one of the survivors told him that the second boat started taking on water when the first boat ran out of fuel.

Italian police said survivors identified the commander of the tow boat as a 28-year-old Sudanese man, who has been arrested and faces possible charges for the deaths. Three other smugglers involved in other crossings also were arrested, police announced.

Italian police tallies indicate some 400 died. But Carlotta Sami, spokeswoman in Italy for UNHCR, put the number of migrants and refugees missing in that incident at 550 based on a higher tally of 670 people on board the second boat. She said 15 bodies were recovered, while 70 survivors were plucked from the sea and 25 swam to the other boat.

Sami said many of the survivors have been traumatized by the shipwrecks.

Most of the people on board were Eritrean, according to Save the Children, including many women and children. One of the survivors included a 4-year-old girl whose mother had been killed in a traffic accident in Libya just days before embarking, said Giovanna Di Benedetto, a Save the Children spokeswoman in Italy.

The UNHCR's Sami also said estimated 100 people are missing from another smugglers' boat that capsized Wednesday off the coast of Libya, captured in dramatic footage by Italian rescuers. And in a third shipwreck on Friday, Sami said 135 people were rescued, 45 bodies were recovered and an unknown numbers of migrants were still missing.

Because the bodies went missing in the open sea, it is impossible to verify the numbers who died. Humanitarian organizations and investigating authorities typically rely on survivors' accounts to piece together what happened.

"The situation is really worsening in the last week," said Di Benedetto.

Survivors of Thursday's sinking were taken to the Italian ports of Taranto on the mainland and Pozzallo in Sicily.

Italy's southern islands are the main destinations for countless numbers of smuggling boats launched from the shores of lawless Libya each week packed with people seeking jobs and safety in Europe. Hundreds of migrants drown each year attempting the dangerous Mediterranean Sea crossing.

Tekle and Selomon both fled mandatory, open-ended conscription in Eritrea. Tekle has been on the move for six years, spending time in Egypt, Israel, Uganda and Sudan before heading to Libya to take the risky sea journey to Italy.

"I want to tell the world this way is dangerous for us. Because my brother, sister, family will lose their lives in this channel," Tekle said as he waited to have his arrival in Italy recorded. "Please help us to have freedom in our country. I don't want to stay here or any place. I want my county with freedom."

Colleen Barry in Milan contributed