POZZALLO, Sicily - Survivor accounts have pushed to more than 700 the number of migrants feared dead in Mediterranean Sea shipwrecks over three days in the past week, even as European ships saved thousands of others in daring rescue operations.
The shipwrecks appear to account for the largest loss of life reported in the Mediterranean since April 2015, when a single ship sank with an estimated 800 people trapped inside. Humanitarian organizations say that many migrant boats sink without a trace, with the dead never found, and their fates only recounted by family members who report their failure to arrive in Europe.
Warmer waters and calmer weather of late have only increased the migrants' attempts to reach Europe.
The largest number of missing and presumed dead was aboard a wooden fishing boat that sank Thursday while being towed by another smugglers' boat from the Libyan port of Sabratha. Estimates by police and humanitarian organizations range from around 400 to about 550 missing in that sinking alone.
One survivor from Eritrea, 21-year-old Filmon Selomon, told the Associated Press that water started seeping into the second boat after three hours of navigation, and that the migrants tried vainly to get the water out of the sinking boat.
"It was very hard because the water was coming from everywhere. We tried for six hours, after which we said it was not possible anymore," he said through an interpreter.
He said he jumped into the water and swam to the other boat before the tow line on the navigable boat was cut to prevent it from sinking when the other went down.
A 17-year-old Eritrean, Mohammed Ali Imam, who arrived five days ago in another rescue, said one of the survivors told him that the second boat started taking on water when the first boat ran out of fuel.
Police said the line, which was ordered cut by the commander when it was at full tension, whipped back, fatally slashing the neck of a female migrant.
According to Italian police, 300 people in the hold went down with the second boat when it sank, while around 200 on the upper deck jumped into the sea. Just 90 of those were saved, along with about 500 in the first boat.
Italian police said survivors identified the commander of the boat with the working engine 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.
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. She said 15 bodies were recovered, while 70 survivors were plucked from the sea and 25 swam to the other boat.
Most of the people on board were Eritrean, according to Save the Children, including many women and children.
Sami also said that estimated 100 people are missing from a smugglers' boat that capsized Wednesday off the coast of Libya, captured in dramatic footage by Italian rescuers.