Two tragedies show the desperate plight of people seeking refuge from war and poverty:

Four children, including a baby girl, were among 71 people found dead in the back of a truck on an Austrian motorway. Meanwhile, 82 bodies washed ashore after a boat packed with migrants sank off the coast of Libya, with about 100 people thought to be missing.

migrants dying to get to europe
Forensic officers stand behind a truck containing a large number of dead migrants on a motorway near Neusiedl am See in Austria, on 27 August 2015Dieter Nagl/AFP
migrants dying to get to europe
Migrants' bodies are covered after being recovered by the Libyan coastguard off the coastal town of Zuwara, on 27 August 2015. The boat packed with mainly African migrants bound for Italy sank off the Libyan coast and officials said up to 200 might have diedHani Amara/Reuters

Libya is a major transit route for refugees and migrants fleeing conflict and poverty en route to Europe. Cross-border smuggling networks exploit the country's lawlessness and chaos to traffic Syrians into Libya via Egypt or nationals of sub-Saharan countries via Niger, Sudan and Chad.

About 198 migrants were rescued from the boat that sank off the Libyan coastal town of Zuwara, a major launchpad for smugglers. Many of the migrants on board, most from sub-Saharan Africa, had been trapped in the hold when the boat capsized, officials said.

Lacking proper navy ships, Libyan officials were searching for survivors with boats provided by fishermen.

migrants dying to get to europe
Migrant children rest at a detention centre in Zuwara after their boat sank off the coast of Libya on 27 August 2015Hani Amara/Reuters
migrants dying to get to europe
Migrants' belongings litter a beach after their boat sank off the coastal town of Zuwara, west of Tripoli, on 27 August 2015Hani Amara/Reuters

The number of refugees and migrants crossing the Mediterranean to reach Europe has passed 300,000 this year, up from 219,000 in the whole of 2014, according to the UN refugee agency UNHCR.

More than 2,500 people have died making the crossing this year. That compares with 3,500 who died or went missing in the Mediterranean in 2014. "The way people are being packed onto boats is causing their deaths," UNHCR spokeswoman Melissa Fleming told a UN briefing.

Fleming said there were legal alternatives to the dangerous journey across the Mediterranean - resettlement and humanitarian admission, with relaxed visa rules and family reunification - but such schemes were "way too few for the numbers of people".

migrants dying to get to europe
The coffin of a dead migrant is taken off a Medecins Sans Frontieres ship transporting 320 migrants in the Sicilian harbour of Augusta on 25 August 2015Antonio Parrinello/Reuters
migrants dying to get to europe
Two men carry the body of a drowned migrant off a Greek Coast Guard vessel, at the port on the island of Lesbos, on 24 August 2015. Two people drowned and five were believed missing when a dinghy carrying migrants capsizedAlkis Konstantinidis/Reuters
migrants dying to get to europe
A suspected smuggler is escorted off an Irish military vessel in the port of Palermo on 6 August 2015, following a rescue operation of a boat carrying over 600 migrants that capsized in the Mediterranean Sea off the Libyan coastMarcello Paternostro/AFP
migrants dying to get to europe
A migrant dives into the water from an overloaded wooden boat during a rescue operation off the coast of Libya, on 6 August 2015Darrin Zammit Lupi/Reuters
migrants dying to get to europe
Migrants hang onto a flotation buoy during a rescue operation off the coast of Libya on 6 August 2015. An estimated 600 migrants on the boat were rescued by the international non-governmental organisations Medecins san Frontieres (MSF) and the Migrant Offshore Aid Station (MOAS) without loss of livesDarrin Zammit Lupi/Reuters
migrants dying to get to europe
A coffin containing the body of an unidentified migrant is carried off the Irish Navy vessel Le Niamh in the Sicilian harbour of Palermo, on 6 August 2015Guglielmo Mangiapane/Reuters
migrants dying to get to europe
Migrants' belongings, including a child's buoyancy ring, litter the deck of a wooden boat from which an estimated 600 migrants were rescued off the coast of Libya, on 6 August 2015Darrin Zammit Lupi/Reuters
migrants dying to get to europe
Surviving migrants are seen swimming in the Mediterranean after a wooden boat packed with up to 700 people capsized and sank off the coast of Libya on 5 August 2015Italian Police/Reuters
migrants dying to get to europe
A migrant prays after 118 people were rescued from a rubber dinghy off a Libyan coast on 3 August 2015Darrin Zammit Lupi/Reuters
migrants dying to get to europe
A coffin containing the body of an unidentified migrant is carried off the Irish Navy ship LE Niamh in the Sicilian harbour of Messina on 29 July 2015. Rescuers found 14 dead migrants on a boat with more than 450 others aboard, off the coast of LibyaAntonio Parrinello/Reuters
migrants dying to get to europe
Coffins of 13 migrants who died in the worst shipwreck in the Mediterranean, on 19 April 2015, are seen during an inter-faith funeral service in Catania, Italy. More than 700 people, most of them locked below deck, were believed to have drownedAntonio Parrinello/Reuters

In one incident on Thursday (27 August), 51 people suffocated in the hold of a boat. Survivors said they had been beaten to force them into the hold and then had to pay smugglers just to come out of the hold to breathe. One of the survivors, an Iraqi orthopaedic surgeon, said he had paid 3,000 euros (£2,200) to come up onto the top deck with his wife and two-year-old son.

Just a week earlier, 49 people died in another boat's hold after inhaling poisonous fumes.

migrants dying to get to europe
A container containing 51 bodies is brought into the Sicilian harbour of Palermo, from Swedish Coast Guard vessel Poseidon, on 27 August 2015. The migrants were found dead in the hold of a boat, and are believed to have been asphyxiated by petrol fumesGuglielmo Mangiapane/Reuters
migrants dying to get to europe
A refrigerated container containing the bodies of 49 migrants who died of asphyxiation in the hold of a boat transporting migrants is unloaded at the port of Catania in Sicily on 17 August 2015Giovanni Isolino/AFP

In the latest tragedy a refrigerated truck found by an Austrian motorway patrol near the Hungarian border had fluids from the decomposing bodies seeping from its rear door. The vehicle had come to Austria from Hungary and is believed to have been abandoned on the highway for at least 24 hours before it was discovered.

migrants dying to get to europe
A coffin is unloaded from a truck outside a customs building with refrigeration facilities in the village of Nickelsdorf, Austria, on 28 August 2015. after a truck containing 71 decomposing bodies was discovered abandoned on an Austrian motorwayHeinz-Peter Bader/Reuters

Hans Peter Doskozil, police chief for the province of Burgenland, said there were "signs" that a Bulgarian-Hungarian trafficking ring was behind the deaths. Of three people arrested in Hungary, one was Bulgarian-Lebanese, another Bulgarian and the third of Hungarian nationality.

Thousands of people from countries like Afghanistan or Syria have fled through the Balkans to Austria, pushing the number of asylum requests to 28,300 in the first six months of 2015 - more than the total for all of 2014.

migrants dying to get to europe
Syrian migrants squeeze under a razor wire barrier as they enter Hungary at the border with Serbia, on 27 August 2015Bernadett Szabo/Reuters
migrants dying to get to europe
Hungarian policemen arrest a Syrian migrant family after they entered Hungary at the border with Serbia, near Roszke, on 28 August 2015Bernadett Szabo/Reuters
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A Hungarian soldier positions a sign at the newly-erected border fence near the town of MorahalomLaszlo Balogh/Reuters

Hungary is fortifying its border, erecting a fence along its frontier with Serbia. Austria's Interior Minister Johanna Mikl-Leitner said the best way to handle the refugee crisis was to create legal pathways into Europe, rather than stricter border controls.