Police in northern Greece say 93 Syrian migrants were released from a locked cargo train carriage, after being tricked by smugglers into travelling in the wrong direction.

The migrants, including 18 children, told police they had boarded the train just over the frontier in Macedonia after paying smugglers 500 euros (£360, $570) each to travel north to Serbia.

The Western Balkan region is seeing a sharp rise in the number of migrants using the route to flee war, poverty and repression in the Middle East and Africa.

Cash-strapped Balkan governments say they are struggling to cope with the influx. Migrants, predominantly from Syria, Afghanistan, Pakistan and North Africa, are trying to walk to western Europe by crossing into Serbia from Macedonia and Kosovo.

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An Afghan woman, followed by her child, walks through a field close to the Greek-Macedonian borderYannis Behrakis/Reuters
migrants Greece Macedonia Serbia Germany
Syrian migrants walk Greece's border with Macedonia in the Kilkis prefecture. Hundreds of Afghan, Syrian and African migrants cross daily from Greece into Macedonia on their way to northern European countries; most of them are turned back by Macedonian border guardsYannis Behrakis/Reuters
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Syrian migrants hide from the authorities as they walk towards Greece's border with MacedoniaYannis Behrakis/Reuters
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Syrian migrants hide as a Greek police patrol van drives on the road near the border with MacedoniaYannis Behrakis/Reuters

Frontex, the agency which co-ordinates the border guards of European Union member states, says the western Balkans route has seen the highest increase of Syrian and Somali nationals illegally entering the EU in recent years.

Frontex estimates that about 43,360 people used the route illegally in 2014, compared to 2,370 in 2010. Some 32,000 arrived in the EU via the Balkans in the first three months of this year, Frontex data shows.

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An Afghan immigrant carrying a toddler crosses the border from Greece into MacedoniaYannis Behrakis/Reuters
migrants Greece Macedonia Serbia Germany
An immigrant from Mali rests at the Macedonian border near the village of Idomeni in the Kilkis prefecture, GreeceYannis Behrakis/Reuters
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A Kurdish-Syrian immigrant Sahin Serko cries next to his seven-year-old daughter Ariana minutes after crossing the border into MacedoniaYannis Behrakis/Reuters
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A young Syrian man walks past a petrol station close to the Greek-Macedonian border in the village of IdomeniYannis Behrakis/Reuters
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A migrant prays in a park near Belgrade's main bus and train stationMarko Djurica/Reuters
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Migrants sleep in a park near the main bus and train station in Belgrade, SerbiaMarko Djurica/Reuters
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Migrants who said they were from Afghanistan are apprehended by the Serbian border police for having illegally entered the country from Macedonia, near the town of PresevoMarko Djurica/Reuters

Macedonia and Serbia both lie on the so-called Trans-Asian corridor, which runs from the Middle East to Europe via Turkey.

In April, 14 migrants were killed when they were struck by a train in a gorge in Macedonia, part of a growing tide of people trying to get to western Europe via the Balkans instead of crossing the treacherous Mediterranean.

Local media said the victims were among a group of around 50 migrants following the train tracks towards Serbia, having probably crossed through Turkey and Greece en route to Hungary and the EU's borderless Schengen zone.

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Media and police inspect the scene where 14 migrants were hit by a train, near Veles in Macedonia, in April Ognen Teofilovski/Reuters
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Azam, a 26-year-old man from South Sudan, stands on rail tracks in Patras in Greece after failing to flee to ItalyYannis Behrakis/Reuters
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An Afghan immigrant walks on rail tracks back to Greek soil after an unsuccessful attempt to make it to Macedonia from the border village of IdomeniYannis Behrakis/Reuters

Every day, migrants in the western Greek port city of Patras risk arrest – and their lives – by climbing under trucks bound for Italy in the hope that by hanging on to the undercarriage they will be transported by ferry to a new and better life.

Locals estimate dozens of migrants make the attempt on a daily basis, overwhelming understaffed port security who chase them away or pull them down as they attempt to scale the port's fence.

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A migrant tries to sneak under a truck that briefly stopped at a traffic light at a ferry terminal in Patras, GreeceYannis Behrakis/Reuters

Many of the migrants come from Sudan, Iran and Afghanistan and live in two abandoned factories opposite the main ferry terminal while waiting to make their move. Some arrived recently, others have lived there for as long as two years.

Mahdi Babika Mohamed's journey started in his native Sudan. He passed through Libya and Turkey before he found himself stuck in Greece, where he has been for seven months.

The rapper, who uses the stage name Twopack, paid a smuggler for sea passage from Libya to Turkey, and then took another boat from Turkey to the Greek island of Samos, before ending up in Patras.

Mohamed says he had successfully managed to reach an Italian port before but was caught and sent back to Greece.

He says he will try again, as returning home is not an option. In Sudan, he says he was a rap artist who had even faced jail time over his controversial lyrics that referenced the Sudanese government.

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Sudanese immigrant Mahdi Babika Mohamed, a rapper with the stage name Twopack, walks downstairs at an abandoned factory in PatrasYannis Behrakis/Reuters
migrants Greece Macedonia Serbia Germany
A Sudanese immigrant prays at an abandoned factory in PatrasYannis Behrakis/Reuters
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Toothbrushes and disposable razors hang inside a deserted textile factory in PatrasYannis Behrakis/Reuters

Germany, favoured destination for many migrants who make it to Europe, has complained that Italy and Greece do too little to track those who arrive and then swiftly head north.