Allegations of callous disregard for Arab and African lives are haunting Europe's politicians as it was revealed that around 800 victims, including an unknown number of children, died in hellish circumstances off the coast of Libya on Sunday.
The migrants had been been locked in the hold or the middle deck of the 20-metre boat, according to survivors, which capsized when it collided with a Portuguese vessel.
UN human rights chief Zeid Ra'ad Al Hussein said the incident had occurred due to a "monumental failure of compassion" by the continent's rulers.
Stung by the full horror of the disaster, the UN Security Council called for a strengthened global response to migration and human trafficking, and the 15-member council voiced support for southern European countries struggling with the refugee influx.
European Commission president Jean-Claude Juncker called for a show of "financial solidarity" towards the countries bearing the brunt of the drama.
Mere "compassionate rhetoric" was not enough, he said during a visit to Austria, whose Chancellor Werner Faymann would like to see massive refugee camps built in North Africa to shelter would-be migrants and refugees.
British Prime Minister David Cameron called for a halt to what he termed the "cargo of death" and the Times reported that Britain was considering sending a warship to help with rescue efforts.
French President Francois Hollande urged Europe "to go much further" in tackling the migrant crisis, and repeated calls for more maritime and aerial surveillance over the Mediterranean.
Hundreds crammed into rickety boats
As the boats get ever more rickety, the numbers crammed into them increase and the chances of catastrophe get higher.
It is not just the scaling back of Italy's naval search and rescue operation that has led to this year's surge in the number of people drowning in the Mediterranean as they seek to reach Europe from north Africa.
At least 1,750 asylum seekers or migrants have perished in the waters between Libya and Italy since the turn of the year, 30 times the total registered in the same period of 2014.
But the dramatically higher death toll does not reflect more people risking their lives to get to Europe: the numbers arriving in Italy are broadly flat - 22,000 up to April 20, compared with 26,600 for January-April 2014, according to the International Organisation for Migration.
"The boats are getting more clapped out and more packed at the same time," IOM spokesman Flavio di Giacomo told AFP. "Whether it is wooden fishing boats or rubber dinghies, the one thing they have in common is that they are always very, very old."
"After a few hours at sea, they start to take on water. That is why it is getting harder and harder to rescue them."
When an Italian coastguard vessel disembarked at Augusta in Sicily last week with 600 migrants rescued from five different boats over the course of two days, the aid workers at the scene all acted as it had been a totally routine operation.
But in reality each of the five incidents involved boats that came perilously close to sinking, according to the migrants on board.
"The water started coming in. We called for help at 1pm and then we waited, and waited," recounted Malik Tourey, a Nigerian who was on board one of the vessels.
"We had to bail out the boat, everyone together, everyone shivering, women crying. It wasn't until 3.00 a.m. the following day that the coastguard arrived."
Italian navy captain Michele Maltese, a spokesman for the coastguard based at Catania on Sicily's eastern coast, said the boats used by people smugglers have always been barely seaworthy.
"What is happening now is they are having more and more people packed onto them," he told AFP.
"On a fishing boat designed for a crew of ten, the traffickers find a way to squeeze between 400 and 500 on board. They become so unstable that a 30-centimetre (one-foot) high wave is enough to result in them taking on water," he said.
"Every boat that puts to sea is doing so at a very high risk (of sinking)."
The traffickers are so cynical they sometimes charge their passengers extra for a life jacket. Maamadou Dialo, who arrived earlier this month, was among those who stumped up, but soon discovered it was far from sound investment.
"It must have been made in China - after five minutes in the water you would have sunk!"
Maltese said Italian authorities tried to ensure traffickers' boats were confiscated and destroyed in Italian ports. But difficult sea conditions meant that was not always possible in the heat of a rescue operation and many are left to drift.
"Human safety is our priority," the coastguard said.
Twice this year traffickers have threatened Italian coastguards with weapons in order to recover and reuse boats from which the human cargo has been taken to safety.
Frontex, the European border agency, interpreted those incidents as a sign that the traffickers are running short of vessels. Others say it simply reflects their belief that they can pretty do what they like in the waters off lawless Libya.