VIENNA (AFP) - Austrian police on Friday raised the number of migrants found dead and decomposing in an abandoned truck on a motorway to 71.
Meanwhile, Libyan rescue workers recovered 76 bodies from yet another capsized boat crammed with desperate people trying to make it to Europe.
In a particularly horrifying tragedy in Europe's unrelenting migrant crisis, Austrian authorities said the bodies found in the truck were likely Syrians and included a toddler and three young boys.
"Among these 71 people, there were 59 men, eight women and four children including a young girl one or two years old and three boys aged eight, nine or 10," police spokesman Hans Peter Doskozil told a packed news conference in Eisenstadt.
Hungarian police said they had arrested three Bulgarians - the owner of the Hungarian-plated vehicle and two drivers, according to Austrian police - and an Afghan and had raided several addresses and confiscated items.
Doskozil said Syrian travel documents were found in the 7.5-tonne refrigerated truck found on Thursday near the Hungarian and Slovakian borders, suggesting the group were "likely" Syrians.
Austrian motorway maintenance workers alerted the police after noticing "decomposing body fluids" dripping from the vehicle, Doskozil said.
Police were confronted by an overpowering stench and a mass of tangled limbs in the truck and forensics experts worked all night to clear out the vehicle.
The state of the corpses suggested that those inside had been dead for some time. Television images showed flies buzzing around the back of the vehicle in the baking sun.
Doskozil said the time and cause of death still had to be determined but there was a "certain probability" they had suffocated.
An AFP reporter said the first 10 coffins arrived for autopsies in Vienna shortly after midday (1000 GMT).
Austrian newspaper Kurier carried a black front page with the headline: "Who will stop this madness?" German Chancellor Angela Merkel, in Austria for a summit with Balkan leaders on Europe's migrant crisis on Thursday, said all those present were "shaken" by the "horrible" news.
"This is a warning to us to tackle this migrants issue quickly and in a European spirit, which means in a spirit of solidarity, and to find solutions," she said.
European Union leaders have struggled to get to grips with a crisis that has seen nearly 340,000 migrants cross the bloc's borders this year - not counting August - and many have come from hotspots like Iraq and Syria.
Millions of other refugees have sought refuge in places like Lebanon, Turkey and Jordan.
Merkel said Friday that EU leaders could hold a special summit on the migrants crisis, but that such a gathering "must be able to take certain decisions".
"If the stink from our car parks gets stronger perhaps we will finally understand, not just in Austria... that it is time to create safe routes to Europe, fast registration and a swift and a fair sharing out (of migrants)," said Amnesty International's Austrian chief Heinz Patzelt.
The United Nations said Friday that the number of refugees and migrants risking their lives to cross the Mediterranean to Europe has soared past 300,000 so far this year.
Over 2,500 men, women and children have drowned trying to reach EU nations after rickety overcrowded boats operated by often unscrupulous people-smugglers capsized.
In the latest disaster at sea, at least 76 people died after a ship carrying hundreds of migrants sank off the coast of Libya, a spokesman for the Libyan Red Crescent said Friday, with 198 rescued.
Red Crescent teams wearing protective white clothing and masks on Friday collected bodies that had washed ashore on a Zuwara beach, placing them in orange plastic bags and carrying them to ambulances.
The United Nations refugee agency, UNHCR, said as many as 200 people on two boats were feared dead.
The Italian coast guard said it had rescued around 1,400 people off Libya on Thursday, a day after it pulled another 3,000 to safety from the same area.
Swedish officials said its ship the Poseidon, docking in Sicily, had rescued 130 people Wednesday from a rubber dinghy and another 442 from a wooden boat found drifting off Libya that also contained 52 bodies.
But the events in Austria have brought home that even when migrants make it across the Mediterranean, their troubles are far from over, with many forced to put their fate in the hands of profit-hungry people-smugglers.
Since the lorry had Hungarian plates, the victims were highly likely among the more than 100,000 people to have trekked up through the western Balkans into EU member Hungary this year.
From Hungary, which is laying a barbed-wire barrier along its border with Serbia to be followed by a four-metre high fence, many migrants try to make it - via Austria - to richer nations like Germany and Sweden.
"We passed by sea. And the sea was just a game playing with our lives," said Lashkari, a 30-year-old Afghan picked up by Hungarian border police on Thursday night after travelling for 30 days.
"I dont think we've reached our final destination yet, because after this we don't know where do we go," he told AFP.