Rescuers and local fishermen were overcome with emotion as they spoke of chaotic early morning scenes in the water off the Italian island of Lampedusa, with "a sea of heads" as desperate refugees waved their arms and screamed.
There were also stories of survival such as a young Eritrean woman thought dead and laid out with other corpses before medical personnel realised she was still breathing and revived her.
Locals on the tiny Italian island of Lampedusa fought back tears as they spoke of the desperate rush to haul dozens of drowning immigrants out of the sea as hundreds around them sank into the black waters.
"We were spending the night on our boat. We heard screams, and we rushed to see what was going on and found a nightmarish situation," Alessandro Marino, a shopkeeper on Lampedusa, told AFP.
"There were between 150 and 200 people in the water. We managed to save 47 of them. Any more and we risked sinking too," he said.
Marino and his friend Sharanna Buonocorso were the first on the scene after a boat with up to 500 African asylum seekers caught fire and sank just a few hundred metres off shore in the worst recent refugee disaster in the Mediterranean.
"Many of them were crying. Lots were naked, to give themselves the best chance of staying afloat," said an exhausted-looking Buonocorso, gazing out over the port where rescuer workers had laid the first victims out in black body bags.
"Many helped pull others from the water, those who couldn't climb aboard by themselves because they had no strength left," she said, describing how the cries for help grew weaker as the minutes passed.
‘They had no chance’
The blue and white flashing lights of coast guard boats could be seen through the darkness as rescue workers continued to trawl the sea where the boat sank, and more divers were being flown in to begin a fresh search of the sunken vessel at dawn.
Local doctor Pietro Bartolo said he had been treating arriving immigrants on Lampedusa since 1991 and had helped survivors of many shipwrecks but had "never seen such a human tragedy on this scale".
"The hardest thing was seeing the bodies of the children. They had no chance. They came here in hope of a future which was snatched from them in a moment. It doesn't take long to succumb to the waves and the cold," he said.
Preparations were underway to receive hundreds of coffins being shipped in from the mainland and Red Cross workers moved back and forth from the port to the airport, where bodies were laid out in a temporary morgue.
Local fishermen and inhabitants of the remote island, where some 6 000 people live among the normally tranquil hills and white-sand shores, said they were used to desperate immigrants washing up on their shores but had never before felt so helpless.
"There was no time. We mobilised boats as soon as we heard what had happened, but for many, for most of the poor souls, it was too late," waitress Rossella Manuci said.
A UN official blamed a repressive policy towards illegal immigrants for the tragedy, while UN chief Ban Ki-moon said he hoped the disaster would be a "spur to action" to protecting migrants' rights, and improving the public perception of immigrants.
Italian Interior Minister Angelino Alfano initially reported "93 victims, including three children and two pregnant women", but rescue divers later said they had identified at least 40 more bodies in and around the sunken wreck.
With only 150 survivors plucked from the water more than 12 hours after the disaster, there were fears that the final toll could rise further to 300 or more people.
Lampedusa is one of the main entry points into the European Union for asylum-seekers crossing from North Africa or the eastern Mediterranean.
Migreurop, a network of immigration charities, estimates 17 000 migrants have died at sea trying to reach Europe in the past 20 years, crossing on rickety fishing boats or dinghies.
Survivors said they were from Eritrea and Somalia and had left from the Libyan port of Misrata.
They told rescuers they set fire to a blanket on the boat to attract the attention of coastguards after their vessel began taking on water and passing fishing boats ignored them.
The fire spread quickly, sowing panic on board, which caused the boat to flip over and sink, as people jumped into the sea to save themselves.
Raffaele Colapinto, a local fisherman who was one of the first on the scene, said: "We saw a sea of heads. We took as many as we could on board."
Visibly shaken survivors in thermal blankets - many of them bare-chested - were seen on the dock and being treated at the hospital where personnel said many had swallowed gasoline and sea water.
'A European tragedy'
The bodies were being taken to a hangar at the local airport because there was no more room in the morgue on the remote island, which has a population of around 6 000 people.
Italian Prime Minister Enrico Letta called the incident "an immense tragedy" and the government declared a national day of mourning on Friday and a minute of silence to be held in all schools.
Alfano called for more assistance from the European Union to deal with the sharp increase in refugee arrivals, calling it "a European tragedy".
About 25 000 people have landed on Italian shores so far this year - more than three times the number for the whole of 2012, although the figure for 2011 at the height of the Arab Spring revolts in north Africa was higher at around 50 000.
In the last major disaster in June 2011, between 200 and 270 immigrants fleeing Libya are believed to have died off the coast of Tunisia.
Many of the arrivals have been on Lampedusa, and most of them have been Eritreans, Somalis and Syrians.
"We no longer have any space for the living or the dead," local mayor Giusi Nicolini said, explaining the cemetery and the refugee centre were full.
Letta "should come here and count the bodies", said the mayor, who often accuses the national government of failing to help the island.
The EU's Home Affairs Commissioner Cecilia Malmstroem called on EU countries to do more to take in refugees, which she said would help reduce the number of perilous Mediterranean crossings.
Pope Francis, who visited Lampedusa in July to plead for more attention to be paid to the plight of refugees, called the disaster "shameful" and urged action to prevent more deaths.
For Francois Crepeau, the UN's special rapporteur on migrants' rights, the "criminalisation of irregular immigration" had played a role in the disaster.
"Treating irregular migrants only by repressive measures would create these tragedies," he said, adding that by closing their borders, European countries are only giving more power to human traffickers.
In Washington, State Department deputy spokesperson Marie Harf extended the "deepest sympathies" of the United States and called on "the international community to work to prevent such catastrophes to these vulnerable migrants".