This undated image made available Monday, May 30, 2016 by the Italian Navy Marina Militare shows migrants being rescued at sea. 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 rescue ships saved thousands of others in daring operations. (Italian Navy via AP)
This undated image made available Monday, May 30, 2016 by the Italian Navy Marina Militare shows migrants being rescued at sea. 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 rescue ships saved thousands of others in daring operations. (Italian Navy via AP)

The treacherous Mediterranean Sea crossing from Libya to Italy has claimed the lives of more than 1,030 migrants in the last week, mostly as barely seaworthy smuggling boats foundered and sank despite calm seas and sunny skies, a migration agency said Tuesday, citing new accounts from survivors.

The staggering death toll foreshadows more disasters ahead in the next few months as the region gears up for its traditional summer-fall spike in human trafficking as the weather improves and the seas grow warmer. Aid officials said it also suggests that Libyan smuggling gangs are using even riskier tactics than before to profit from the torrent of those desperate to reach the safety or economic promise of Europe.

Making matters worse, the jaw-dropping tally is only from capsizings or shipwrecks that are known to authorities, who readily admit they simply do not know how many people are being cheated by smugglers, jammed into obviously unsuitable vessels and swallowed up by the vast waters of the southern Mediterranean.

Two Eritreans interviewed were haunted by the fact that so many women and children had been on their capsized boat and did not survive. They said they could still hear the cries of the children.

“I started to cry when I saw the situation and when I found the ship without an engine. There were many women and children,” said 21-year-old Filmon Selomon who plunged into the sea to save himself. “Water was coming in from everywhere, top, bottom.”

“The children were crying and the women,” said Habtom Tekle, a 27-year-old Eritrean. “At this point, I only tried to pray. Everybody was trying to take the water out of boat.”

U.N. refugee spokesman William Spindler told reporters at a news conference in Geneva that this year is already proving to be “particularly deadly” on the Mediterranean, with some 2,510 lives lost compared with 1,855 in the same time span a year ago.

The International Organization for Migration, citing what could be a record weekly death toll on the Mediterranean by its count, said Tuesday that 62 people were confirmed dead and 971 were missing and presumed dead in nine separate deadly emergencies since May 25 on the Libya-to-Italy sea route.

The U.N. refugee agency said Tuesday it had tallied at least 880 deaths on the Mediterranean over the last week. Spindler noted such estimates are an inexact science, and said his agency’s figures tend to be “conservative.”

Last week marks only the second time since January 2014 that 1,000 deaths or more on that route have been tallied in a single month – let alone a single week, said IOM spokesman Joel Millman. The only other time was in April last year, with 1,244 dead.

He said up until last week, only 13 migrant crossing deaths had been recorded in May in the southern Mediterranean.

Spindler gave the following estimates: about 100 people died in a shipwreck Wednesday; some 550 others died in another capsizing Thursday, the one that the two Eritreans survived; and a third sinking Friday left 170 others missing and presumed dead.

The discrepancy between the agencies stems largely from Wednesday’s sinking: IOM now estimates that 250 people died. Like UNHCR, it had originally estimated about 100 deaths.