(CNN) Italian and Hungarian authorities made arrests in the deaths of migrants and refugees this week, including 71 whose bodies were found in an abandoned truck in Austria.

Those who died in Austria -- most likely fleeing war-ravaged Syria -- probably suffocated inside the truck abandoned on a highway, authorities said Friday.

Sixty of the 71 victims were men. Eight women died, as did three children, ages 2, 3 and 8.

"We are talking about human trafficking, homicide, even murder," said Johann Fuchs, state prosecutor of Eisenstadt.

News of the deaths comes as Europe is struggling to deal with a record swell of migrants and refugees traveling by land and sea to find a better life or escape conflict at home in the Middle East and Africa.

United Nations officials have called on European officials to improve their efforts to resolve the growing humanitarian crisis, including dealing with human traffickers preying on refugees.

"This tragedy underscores the ruthlessness of people smugglers who have expanded their business from the Mediterranean Sea to the highways of Europe," said Melissa Fleming, a spokeswoman for the office of the United Nations High Commissioner for Refugees. "It shows they have no regard for human life and are only after profit."

The truck was found Thursday, abandoned on the side of the A4 highway, which links Budapest in Hungary to the Austrian capital, Vienna. When police opened it, they found the bodies decomposing in the heat.

They found a Syrian travel document inside the truck.

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"We must assume now that these are refugees," said Hans Peter Doskozil, police director of Austria's Burgenland region. "In concrete terms, it is possible this is a Syrian refugee group."

Hungarian police said they had arrested three Bulgarian citizens and an Afghan citizen in connection with the truck.

"We are likely looking at a Bulgarian-Hungarian people smuggling ring," Fuchs said.

About 3,000 trucks pass through that area of the highway daily, and checking each one of them is almost impossible, authorities said. Most human smugglers use smaller cars, making the use of trucks unusual.

Deaths in the Mediterranean

In addition to the deaths of refugees trying to cross into Europe by road, thousands are making the perilous journey by sea.

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Italian authorities said Friday they had arrested 10 people on suspicion of multiple homicide in the discovery of 52 bodies aboard a boat packed with migrants and refugees off the coast of Libya this week, police in Sicily said Friday. The suspects could also face additional charges of aiding illegal migration and kidnapping, according to police.

Two boats carrying hundreds of people from various nations capsized near the Libyan city of Zuwara, killing at least 84 people, officials said Friday.

At least 198 people have been rescued, while 18 others remain missing, said Mohammed Al-Misrati, a spokesman for the Libyan Red Crescent.

One of the boats went down Wednesday, while a second one capsized Thursday, he said.

The Red Crescent, along with the Libyan coast guard, rescued dozens of people from African countries and from Syria

In all, some 300,000 people have crossed the Mediterranean Sea into Greece and Italy this year alone, according to the office of the United Nations High Commissioner for Refugees.

Of those, at least 2,373 have died, according to the International Organization for Migration.

Survivors of sea passages told harrowing tales, the United Nations' Fleming said, such as being charged money to come out of the ship's hold to breathe.

She said a 25-year-old man from Sudan told United Nations employees, "We didn't want to go down there but they beat us with sticks to force us. We had no air so we were trying to get back up through the hatch and breathe through the cracks in the ceiling. But other passengers were scared that the boat would capsize so they pushed us back down and beat us, too. Some were stomping on our hands."

Comprehensive response urged

United Nations officials are calling on European leaders to organize a collective response to the needs of migrants and refugees flooding the continent.

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"UNHCR hopes this incident will result in strong cooperation among European police forces, intelligence agencies and international organizations to crack down on the smuggling trade while putting in place measures to protect and care for victims," Fleming said.

The deaths in Austria highlight the need for a better strategy, Austrian Interior Minister Johanna Mikl-Leitner said.

"This horrible crime shows that we must get even tougher in the battle against people smuggling," she said. "People smugglers are criminals and not well-minded helpers. They do not care about the well-being of the refugees, they care about profit."