In the southern Italian region of Puglia, the cliffs of the Gargano peninsula stretch out into the Adriatic Sea, offering breathtaking views. Its beaches are a magnet for tourists, but the area is also a key agricultural center.

Italy's processed tomatoes are sold around the world, and about a third of them are produced here, in the province of Foggia.

But far from its tourist-packed beaches, the region is scattered with makeshift camps, known locally as ghettos, that are home to a migrant workforce that plants and harvests its crops.

Italy's biggest labor union, CGIL, estimates that up to 12,000 migrants live in these camps in abject conditions. In some of these places, migrants say, the lack of basic services such as running water, electricity or waste disposal can have fatal consequences. Italian media reports that four migrants have died in such camps just in the last year: one of hypothermia, three in fires.

These makeshift communities are home to both legal and undocumented migrants from all over the world. They include EU citizens, often from Romania and Bulgaria, Afghans and Pakistanis, but most residents are young men from Africa.

They come here to find work as day laborers. But, according to labor unions and the national and regional government, many are exploited -- forced to work long hours and earning far below the minimum wage.

A US flag bearing Jim Morisson's face flies next to an Italian flag, amid the makeshit homes of the "Runway Ghetto," in Foggia.

Working for the gangmasters

When local farmers need to find cheap, readily available hand-pickers, rather than employing them directly, they largely turn to middlemen known as "Caporali"-- gangmasters.

These gangmasters take a share of the workers' wages and often charge them for transport to the fields, as well as the food and water they receive while there.

Raffaele Falcone is a legal expert who works for CGIL, Italy's biggest labor union. He gives an example of how it works: "One big landowner in this area uses a gangmaster from Morocco, who has 10 vans and employs drivers from the ghetto.

"For each 300-kilo box of tomatoes filled by the workers, the landowner gives €5 ($5.80) to an Italian middle-man who deals with the gangmaster. After they both take their cut, the worker gets €3 ($2.5). Migrants are charged €5 for transport. Sometimes five more for food."

The legal minimum wage for laborers in this province is €53 ($62) per day. Working hours are limited to six-and-a-half hours a day, with a maximum of three hours overtime per day.

For months, Falcone and his colleagues have been visiting the camps to convince migrants to report the abuse they suffer.

He says that since September he has logged 34 detailed stories of exploitation, where migrants were found to work under a gangmaster, with no employment contract, and for more than 10 hours a day.

Some cases involved violence -- one reason why most workers are too afraid to speak out, according to Falcone. Because they live in camps where law enforcement is virtually absent, he says, migrants are exposed to the retaliations of the gangmasters, who have the power to starve them for work and harm them physically.

The Runway Ghetto is located at the site of a former military airport.

Life in the 'Runway Ghetto'

Aly Muhammad, 19, left Mali when he was 16. Now he lives in a camp of migrant workers that has grown up next to Borgo Mezzanone, a rural hamlet of 500 residents. Here, a decommissioned military airport has grown into a makeshift community made of containers, tents and shacks, known as the "Runway Ghetto."

Different sections of the runway host different communities, with their own churches, mosques, corner shops, butchers and even nightclubs.

Muhammad says that during the year he spent in Libya on his way to Italy, he was imprisoned and tortured by militias in Tripoli until his family sent him the equivalent of $600 to pay for his release. But nothing angers him more than the treatment he received in Italy.

"How can a first world country keep people living like this?" he says.

Pastor Charles, at the Nigerian church in the Runway Ghetto.

Muhammad no longer toils in the fields, now working as a mechanic in his camp. Because he doesn't answer to farmland bosses, he says he is not afraid to speak of the abuse he witnessed during the short time he spent in agriculture.

"I have seen my brothers breaking their backs under the sun for 12 hours, and then being denied their wage," he says. "If they complained, the Italian landowner would beat them up."

CNN contacted the Interior Minister's special delegate assigned to deal with public order and health issues arising from the presence of the illegal camps. The office, after initially agreeing to an interview, said the special delegate was no longer available to discuss the issue of camp conditions.

Breaking the system

The governor of Puglia, Michele Emiliano, called upon businesses to break the gangmaster system by only employing migrants legally.

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Emiliano told CNN that farmers using gangmasters can have their land seized, the result of a tough anti-exploitation law passed in 2016, in the wake of the death of Italian grape-picker Paola Clemente. She was working in the fields of Puglia earning €2 an hour ($2.4) when she died of a heart attack, aged 49. The judicial investigation into her case found that her recruiters took advantage of her vulnerable economic conditions to extort her wage and impose extreme working conditions.

The new law means that those found to be hiring workers through gangmasters who exploit laborers can face up to eight years in prison. And the law offers victims of labor exploitation the same protection and resources available to victims of sex trafficking, such as access to professional training opportunities.

Trash litters the fields around the Runway Ghetto.

In July, in a landmark anti-slavery case in Lecce, at the southern end of Puglia, public prosecutors obtained heavy jail sentences for eight gangmasters and three landowners.

Court documents from the case, seen by CNN, reveal a scheme where landowners trafficked migrants directly from Tunisia to secure cheap labor. Every few weeks, gangmasters rotated the workers around camps and employers in other Italian provinces, including Foggia, hundreds of miles away from each other, in order to keep them vulnerable.

Judicial initiatives on a comparable scale haven't been seen in Foggia. But some landowners here feel that the new anti-exploitation legislation targets them unfairly. They say they require a flexible workforce, and because they don't speak the language or understand the culture of their migrant laborers, the best way of hiring them is through middlemen.

"Now we are treated as gangmasters" protests Enzo Smacchia, who owns 40 hectares of cultivated fields in Puglia and says he pays his workers a fair wage. "Why don't the authorities focus on all the crime and prostitution that goes on in the ghettos?" he says.

Farmer Enzo Smacchia says he pays his workers a fair wage.

Smacchia feels that medium-sized landowners like himself are victims of the retail sector, which he says has driven down prices for tomatoes, leaving migrant workers vulnerable to exploitation.

The public prosecutor for Foggia, Francesca Pirrelli, said: "Labor exploitation originates in the absence of job centers and in the great poverty of this province, which is driven by the prices made by the retail sector."

Pirrelli now heads a newly established task force dedicated to fighting the gangmaster system. She says there will be a major a crackdown next spring, when the harvest begins.

"The law now allows us to seize land, which is the most effective deterrent against this sort of crime," she said.

Emiliano says that Italy's Interior Minister made a personal commitment to provide witness protection to both companies and workers who come forward to report abuse.

Camp evictions

The regional government says it is taking a tough stance on the migrant camps. Emiliano describes these places as being "controlled by criminal organizations dedicated to prostitution, drug dealing and caporali."

Burning trash at the Runway Ghetto.

Residents have been evicted from some camps and Emiliano says more evictions are imminent. He says that evicted migrants can move to structures provided by the regional government, with free access to food and sanitation facilities, where they will be free from the exploitation of gangmasters. Only 1,000 beds are currently available at these regional reception centers, but the administration is planning to build more by the next harvesting season.

As winter approaches, fewer laborers are needed in the fields; some migrate further south, to harvest oranges; some go to the industrial cities of the north. Inside the camps, the thousands who stay become more dependent on the illegal economy. Improvised heating systems increase the risk of fires, but the cold is a more imminent threat.

On December 16, a group of migrants from the ghettos will march in Rome to demand an end to labor exploitation, and to voice their right to safe and decent housing.

They believe that until workers organize, things won't really change. One of their slogans is: "You wanted manpower, you found men."