Novi Pazar, Serbia: In a once-abandoned factory deep in Serbia’s southern mountains, migrants bring pots of tea to the boil as snow drifts blanket the surrounding ravines and peaks.

From Syria and Somalia, the Democratic Republic of Congo and Ivory Coast, Iran and Afghanistan, all are here – a state-run reception centre for asylum seekers in the Serbian town of Tutin – after bruising and furtive journeys across deserts and through forests, escaping conflict and upheaval in their homelands.

Within days most will be back with smugglers, heading north towards Hungary – but with a fierce determination to reach western Europe.

“I love my country. Eritrea is a beautiful place,” says a 34-year-old woman called Janet, from the tiny east African state. “But we have a dictatorship. I want to live in a good country, in peace, where I can have a good life.”

Sipping on a glass of ginger-spiced tea she recalls being smuggled with some 20 other people through Eritrea’s notorious border minefields late last year, into Sudan

They trekked onwards to the ramshackle Sudanese capital, Khartoum. She left behind her husband and 11-year-old son, fleeing years of enforced national service in Eritrea – where Human Rights Watch says conscripts are routinely used as forced labour – late last year.

“We had no money, no food,” she says. “No life.”

Janet scrimped away donations from relatives until she had enough to buy a Sudanese passport from a corrupt official. She boarded a plane bound for Istanbul, the entry point to the “Balkan corridor”.

“I had friends who knew smugglers there,” she says. “I got in touch with them through text message.”

Within three days of arriving in Istanbul she was connected. Smugglers could get her to Greece and then to the region’s well-established smuggling routes. At a price.

Small boats ferry migrants from Istanbul or further down Turkey’s western coast to Greece, or up the Bosphorus and along the Black Sea coast to Bulgaria or Romania.

Others attempt to enter the Balkans by foot, walking for days through mountain and forest into Bulgaria or Greece, looking north to Hungary. Bulgaria recorded some 38,000 attempted entries for 2014.

“Most people entering Bulgaria share the same story. They hire a smuggler in Istanbul or Edirne [in northern Turkey] and are part of a group of a dozen or 20 people,” says Boris Cheshirkov, of the United Nations’ refugee office in Sofia, Bulgaria.

“The smugglers will not cross the border with the group, leaving them in the vicinity of the border and instructing them to walk in a certain direction.”

On their trek, the migrants often have another companion: violence. In early April, a group of Syrians were severely beaten in the southern Serbian town of Bujanovac by a mob of Roma, in a bungled robbery.

Another two Syrians were hit by a train just outside the same town, their corpses mutilated, after having walked into Serbia from Macedonia along the railway tracks.

“It was a tragedy,” says Sheikh Ulvi Fejzullahu, who oversaw the burial of the men. “At this mosque we made certain that our congregation attended the burial. They are human beings and deserve respect.”

A few short days after those deaths, another 14 migrants were crushed by a train on the very same tracks while walking through a gorge in Macedonia.

Serbian police have subjected migrants to “violent assaults, threats, insults, and extortion, denial of the required special protection for unaccompanied children, and summary returns to the Former Yugoslav Republic of Macedonia”, according to Human Rights Watch.

Bulgarian border agents are believed to have similarly “pushed back” asylum seekers. In one high-profile case, two Yazidi men, fleeing the clutches of Islamic State in Iraq, froze to death after a beating by Bulgarian authorities broke their legs as they attempted to enter the country illegally.

Some 1500 police have been deployed to an area of the Bulgarian frontier known as the Green Zone, an attempt to cauterise the flow of migrants entering the country on foot from Turkey.

The construction of a 33-kilometre razor wire border fence, with a planned 82-kilometre extension still to be erected, has forced the Bulgarian route to evolve, driving demand for the services of organised groups of smugglers.

“Now, the majority of people are coming through the official crossings but concealed in cargo trucks and freight trains,” says Cheshirkov. “These are smuggling rings and they easily adapt to a situation.”

Others talk of abuse at the hands of smugglers. They are jammed into freight trucks – the domain of organised crime – and driven across Greek and Bulgarian borders, snaking their way north.

“[In Athens] the smugglers took us to a room with maybe 50 people,” says 25-year-old Abdul Nasser, from Mogadishu, Somalia, resting at the reception centre in Tutin after weeks traversing Albania and Montenegro with an organised crime gang. “They beat all of us again and again, making us call our families to send money.”

All are meantime viewed with distrust by an increasingly xenophobic and right-wing Europe. In one example in Bulgaria, residents of a village refused to allow a refugee child – whose family had been granted asylum – to attend the local school.

Janet, arriving in Greece on foot, moved into a home with other migrants in Athens. After a month of waiting she walked 10 days into Albania, paying smugglers $US1500 ($1900).

It was there she began to travel with better-organised smugglers, by van and truck, aiming for the porous Sandzak, a zone divided between Serbia and Montenegro.

The Balkan’s multi-ethnic crime syndicates have a formidable reputation and global reach. In the southern Serbian town of Veliki Trnovac – the heart of the Kosovo Triangle, marked by Interpol as a blackspot on world drug routes – villas sprawl and luxury cars with French and Swiss numberplates sit unused, except for a brief period over the northern summer when their owners return home.

It is an odd fit for one of the poorest regions in Serbia, wracked by soaring unemployment and crumbling infrastructure.

“We do have some people from here involved in this dirty business, with the narco-mafia and people smuggling,” says Shaip Kamberi, a Serbian MP for Veliki Trnovac. “But it cannot survive unless some people are closing their eyes – at the border, for example.”

Following the collapse of Yugoslavia, Albanian businessmen from this town, and others in the Presevo Valley, spread their roots wide, establishing a global network fronted by legitimate businesses trading leather, for example, to facilitate and disguise illegal activity.

Notorious for fierce loyalty to family and clan and ruthless violence, they overwhelmed the Sicilian mafia in the early 2000s and penetrated deep into the US, South American and western European black markets.

They cornered the opiate trade in Turkey, aligning with corrupt figures from the Turkish military establishment and established partial control over the Balkan land, sea and air heroin routes.

Yet they deal in everything. Narcotics, people, arms, prescription pills and liquid mercury. At one stage in the late 1990s, an Albanian syndicate was reportedly shopping around containers of radioactive material.

“Money talks and business is business, regardless of whether it is smuggling cigarettes or people,” says a security expert with experience in the Balkans. “To keep your place in the crime world you need a reputation.”

In one recent case, a man was caught driving a rental van stacked with migrants in Bujanovac, whom he picked up near the Macedonian border.

According to a municipal figure privy to the case, but not authorised to speak to the press, the 37-year-old ethnic Serb admitted to having been instructed to drive the migrants to Hungary. He refused to reveal who hired him for the job and was released within a week.

In another, a Greek and a Hungarian man were caught with a small group of migrants in a van, having seemingly driven through Bulgaria to collect their cargo in southern Serbia. For such syndicates, according to Interpol, people smuggling is “low risk and high profit”.

“We have different jobs. Some people drive them, some people pick them up, some people arrange times, and drivers,” says a Turkish scout who stalks Istanbul’s streets searching for migrants.

Migrants are then shuttled on to Greece or Bulgaria, where a different, yet linked network takes over. Each step of the way, the migrants pay.

“You can’t pay, you get f—ed up,” the scout says. “If you’re a criminal with a warrant, it costs more.”

Everyone takes a cut as the money rises up the various layers of various networks. “We can get cargo trucks, cars with hidden compartments,” says the Turkish scout. “Depends on what you need.”

And the need is surging. Syria’s civil war continues to send a flood of people into neighbouring countries.

One family, from the Syrian city of Aleppo, walking exhausted and dehydrated just north of Presevo town, had just been smuggled across into Serbia. They offered €300 ($420) to be driven to Subotica in the north, near the Hungarian frontier.

“We lost everything,” said the father, Mohammed, his infant child cradled in his arms. “It took us 11 days to get here, from Skopje (Macedonia’s capital).”

Janet, having reached Albania, was shuttled north in vans through Montenegro – a route along the Adriatic coast dotted with casinos – eventually reaching Serbia. She registered as an asylum seeker and sought shelter in the Tutin centre.

“I hope I will be in Hungary in a week,” she says. “When I get to [western Europe], God willing I can help my husband and son get there.”

A few days later she was in a house near Belgrade, heading towards Subotica. “Tomorrow,” she said, via Facebook, “I will be in Hungary.”

Then, a few days later, a single message: “Budapest.”